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MEGAGAUSS MAGNETIC FIELD GENERATION, ITS APPLICATION TO SCIENCE AND ULTRA-HIGH PULSED-POWER TECHNOLOGY This page intentionally left blank MEGAGAUSS MAGNETIC FIELD GENERATION, ITS APPLICATION TO SCIENCE AND ULTRA-HIGH PULSED-POWER TECHNOLOGY Proceedings of the Vlllth International Conference on Megagauss Magnetic Field Generation and Related Topics Tallahassee, Florida, USA 18-23 October 1998 Edited by Hans J. Schneider-Muntau National High Magnetic Field Laboratory Florida State University, USA NEW JERSEY * LONDON * \: World Scientific SINGAPORE * EElJlNG * SHANGHAI * HONG KONG - TAIPEI * CHENNAI Published by World Scientific Publishing Co. Pte. Ltd. 5 Toh Tuck Link, Singapore 596224 USA ofice: 27 Warren Street, Suite 401-402, Hackensack, NJ 07601 UK ofice: 57 Shelton Street, Covent Garden, London WC2H 9HE British Library Cataloguing-in-PublicationData A catalogue record for this book is available from the British Library. The editor of this book wishes to thank those who worked so hard to make the conference such a success. A greater challenge turned out to be the peer review of all the articles and the editing of the book. The untiring efforts of Ms. Pam Houmere for the technical editing of the papers are especially recognized. Without her help this book would not have been possible. Many thanks also go to the people who helped over the years with the follow-up on the collection of the original and reviewed papers: Ms. Terry Pace, Janet Neff-Shampine,again Pam Houmere, and others. The peer review of the papers and the book was produced with ultimate care. Nevertheless,we cannot warrant the information contained in this book to be free of errors. The quality of the pictures, figures, and equations stems from the originals we received from the authors. Particular thanks go to Mr. Walter Thorner for the design and lay-out of the book. On the Cover: The National High Magnetic Field Laboratory in Tallahassee, Florida with a reproduction of the 2800 T (28 MGauss) field pulse obtained in; Sarov in 1998. MEGAGAUSS VIII Proceedings of the VIII International Conference on Megaguass Magnetic Field Generation and Related Topics Copyright 0 2004 by World Scientific Publishing Co. Pte. Ltd All rights reserved. This book, or parts thereof; may not be reproduced in any form or by any means, electronic or mechanical, includingphotocopying, recording or any information storage and retrieval system now known or to be invented, without written permissionfrom the Publisher. For photocopying of material in this volume, please pay a copying fee through the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, USA. In this case permission to photocopy is not required from the publisher. ISBN 982-256-016-5 This book is printed on acid-free paper. Printed in Singaporeby Mainland Press Vlllth INTERNATIONALCONFERENCE ON MEGAGAUSS MAGNETIC FIELD GENERATION AND RELATEDTOPICS Tallahassee, FL, USA, October 18-23, 1998 This page intentionally left blank DEDICATED TO THE 80th BIRTHDAY OF MAX FOWLER Max Fowler, 1998 During the “Megagauss VII” Conference in Sarov, the International Steering Committee voted to ask the National High Magnetic Field Laboratory to host the next “MegagaussVIII” Conference in Tallahassee, Florida, U.S.A. and to dedicate it to the 80Ih birthday of Dr. Clarence M. Fowler, known simply as “Max” to his many friends and colleagues. By this decision, the International Steering Committee emphasized not only the outstanding contribution of Max Fowler as a pioneer in the field of megagauss magnetic field generation, design of generators of magnetic fields and electromagnetic energy, and the application of the generators to various problems of experimental physics, but especially his outstanding contribution to the creation of the International Megagauss Community. It is a great honor for us to write this short article about Max, our wonderful colleague and friend. To write about Max is simultaneously easy and difficult. There are two attributes which we find remarkable; his outstanding scientific success, because many of his papers became classical and well known to the scientific community, and his scientific drive infecting everyone he met with his enthusiasm and passion for research. Max Fowler was born in November 26, 1918, in the small town of Centralia, Illinois, U.S.A. He obtained a B.S. degree in Chemical Engineering from the University of Illinois in 1940. After graduation, he worked at the American Steel and Wire Company in Cleveland, Ohio. There, he met his future wife, Janet Brown. Max and Janet will soon celebrate their 60Lhwedding anniversary. Following the outbreak of WWII, he enlisted in the Navy. Upon his discharge in mid 1946, he enrolled as a graduate student in Physics at the University of Michigan. After completing his graduate work in late 1949, Max accepted an appointment at Kansas State University (KSU) as Assistant Professor. He set up a laboratory at KSU dedicated mainly to the beta and gamma ray spectroscopy of neutron induced radioactive rare-earth elements. In the early 1950’s, he started at the Los Alamos Scientific Laboratory as a summer Visiting Scientist. It was during these visits that Max fired his first flux compression shots. He eventually resigned from his position as Full Professor of Physics at KSU in 1957 to devote all of his time to a broad program in Magnetic Flux Compression at Los Alamos. vIIthINTERNATIONAL CONFERENCE ON MEGAGAUSS MAGNETIC FIELD GENERATION AND RELATED TOPICS. TALLAHASSEE, FL, USA, OCTOBER 18-23, 1998 A pioneer himself, Max is linked to early pioneers such as Peter Kapitza and Francis Bitter. Bitter worked as a consultant during many summers in Los Alamos developing new designs of pulse magnets to increase the seed field of flux compression devices. Max is also connected to another pioneer, Heinz Knoepfel, who developed a flux compression facility with Fritz Herlach in Frascati, Italy. Dr. Fowler is the author or coauthor of nearly 200 open-literature publications on such different subjects as difference equation stability, diffusion, nuclear spectroscopy, shock wave induced phase transitions and other effects in metals, and most predominantly in explosive flux compression. Over the years, he and his colleagues have utilized explosive flux compression to produce very large magnetic fields and to generate large electromagnetic pulses. They have used both techniques in many applications, including megagauss field generators for solid state research, pulsed power supplies for a number of devices including theta pinches, plasma guns, plasma focuses, lasers, imploding foils for soft X-ray production, e-beam accelerators, rail guns and, more recently, as magnetic field generators to study hightemperature superconductors in megagauss fields. We mention here explicitly three of Max’s especially worthy publications. His very first paper was titled “Analysis of Numerical Solutions of Transient Heat Flow Problems” [l]. Max is very proud of this paper. He told us that he has received the most reprint requests for this paper. His contribution was awarded the Miller Prize in mathematics at the University of Michigan. Max’s most significant and well-known paper is the “Production of very high magnetic fields by implosion” .It was the first report of magnetic field generation above 10 MG and up to 14 MG. It stimulated much work in liner implosion of plasmas, material research in megagauss fields and ultimately, the Megagauss Conferences. Let us note that it took almost 40 years to double the field value to 28 MG as reported at this conference . As the third paper, we wish to cite the review paper at this conference  where Max gives a thorough overview of his work in flux compression. Max’s earlier work had a strong influence on subsequent megagauss-field solid-state research, liner implosion of plasmas, and on the initiation of the International Conferences on Explosive Generation of Megagauss Fields and Related Topics, now known as the Megagauss (MG) Conferences. Dr. Fowler chaired the MG Conference held in Santa Fe, NM in 1986 and, as a member of the International Steering Committee, assisted in organizing most of the other Megagauss Conferences. Relations with Russian colleagues, within limitations imposed by the political climate of those times, were greatly stimulated by the relationship that developed between Fowler and Gennady Shvetsov, of the Lavrentyev Institute of Hydrodynamics in Novosibirsk. This collegial relationship then led to one with the late Academician Alexander Pavlovski, who directed a similar flux compression effort at Sarov, a complex similar to Los Alamos and now Los Alamos’ “sister city”. The existence of the subsequent, unclassified scientific programs carried out jointly between these two “weapons” laboratories, was due in considerable part to the Pavlovski-Fowler relationship. It was their profound friendship and the peaceful scientific cooperation that helped to break the ice between the U.S. and Russia at the end of the cold war. Max was also instrumental in helping the Florida State UniversityiUniversity of FloridaiLos Alamos Proposal to develop the National High Magnetic Field Laboratory partly due to the high magnetic field research done at Los Alamos by the Explosive Flux Compression Team. Dr. Fowler has served on a number of panels and committees including the National Science Foundation Panel on High Magnetic Fields, the Defense Science Board, NATO, DOE, DoD, and has directed a number of programs for some of these organizations. He Megagauss Magnetic Field Generation, i t s Application to Science and Ultra-High Pulsed-PowerTechnology is a long-time Fellow of the American Physical Society (1964) and was one of the early Los Alamos National Laboratory Fellow Appointees (1982). Dr. Fowler was awarded an Honorary Doctorate from Novosibirsk State University for his work in high energy density physics and for furthering scientific relations between the United States and Russia. He was honored in a special session of the MG VIII Conference held in Tallahassee in 1998. Although retired for several years, he has remained active in both publishing and lecturing. In the last two years, besides lectures in the US., he has presented lecture series in Korea, Russia and Germany. At the special session of the MG-VIII Conference at which friends and colleagues congratulated Dr. Max Fowler on his anniversary, conference participants of the Lavrtentyev Institute of Hydrodynamics read out the following congratulation: “Dear M a , In everyone j . life there happen events that can be considered the most important andyears later the person realizes better and better how many things in his personal life would be dijferent if this event did not occur For us, such an event was the acquaintance and cooperation with you. In yourperson we have an outstanding scientist, a reliable friend, and a wonderful man. Today, many-many years after ourJirst meetings in Los Alamos and Novosibirsk, we thank our lucky stars that we have the good,fortune to know and love you and work together with you. Our hearts are with you and your incomparable Janet. On the occasion ofyour 80th birthday we wish you good health andgreat success.” We would like to conclude this dedication by joining in the above wishes,from the depth ofour hearts. Gennady A. Shvetsov Hans J. Schneider-Muntau References 1. Fowler, C. M., Analysis of Numerical Solutions of Transient Heat Flow Problems, Quart. Appl. Math. 3 (1946) p. 361. 2. Fowler, C. M., Gam, W. B., Caird, R. S., Production of Very High Magnetic Fields by Implosion, J. Appl. Phys. 31 (1960) p. 588. Also, Bull. Am. Phys. Sac., 4 (1959) p. 96. 3. Boyko, B. A,, Bykov, A. I., Dolotenko, M. I., Kolokol’chikov, N. P., Markevtsev, 1. M., Tatsenko, 0. M., Shulvalov, A. M., Generation of Magnetic Fields Above 2000T with the Cascade MagnetoCumulative Generator MC-1, this conference. 4. Fowler, C. M., Explosive Flux Compression: a Review of 50 Years of Los Alamos National Laboratory Activities, this conference. vIIthINTERNATIONAL CONFERENCE ON MEGAGAUSS MAGNETIC FIELD GENERATION AND RELATED TOPICS. TALLAHASSEE, FL, USA, OCTOBER 18-23, 1998 This page intentionally left blank EDITOR'S PREFACE The generation of megagauss fields for science and technology i s an exciting area where new physical phenomena, technological challenges, and the selection and development of materials together create a unique potential and synergy resulting in fascinating discoveries and achievements. The controlled handling and applications of extremely high power and energy densities in small volumes and on short time scales i s the common theme of this collection of contributions. A l l papers have been peer-reviewed and carefully edited. The Vlllth International Conference on Megagauss Magnetic Field Generation and Related Topics (MG-VIII) united more than 200 participants from over 14 countries, with 87 delegates from the U.S. and 30 from Russia. These Proceedings provide the latest research results on the generation of very high magnetic f elds up to and well above the megagauss level. One of the highlights i s the report on the highest magnetic field ever generated, 2800 T (28 MG), using explosive flux compression technology. An entire session i s devoted t o the Dirac series of scientif c experiments in fields up to 1000 T. Contributions about the generation of fields in the millisecond pulse range, f elds in small volumes, and material developments in this area, conclude the f rst section of the Proceedings. Megagauss Vlll was held in connection with the conference “Physical Phenomena at High Magnetic Fields - 111” (PPHMF-Ill) in order to encourage and facilitate cross-links between the two scientif c communities. This was highly successful since 26 PPHMF participants also registered at MG-VIII. The chapter “Science in Megagauss Magnetic Fields” ref ects these contributions. The following section of the Proceedings i s devoted to new results in the more traditional fields of the Megagauss conference: generation of plasmas, magnetized plasma, imploding liners, and fusion. Two major chapters describe progress with generators that use explosives to create ultra-high pulsed power for different applications, and other activities such as rail guns and launchers, codes and modeling. All of these contributions underline the ever-growing importance of advancing ultra-high power density technologies. The Proceedings close with descriptions of magnetic f eld facilities that are open to users who wish t o do experiments in high and ultra-high magnetic f elds. The conference organizers want to thank the members of the International Steering Committee, the Program Committee, and the Local Organizing Committee. Help and assistance by the Megagauss Institute Inc. i s especially recognized. Our gratitude also goes t o the numerous conference sponsors who helped to make the conference become such a congenial and successful meeting. It i s impossible t o acknowledge all those who helped to organize the conference. Special thanks go t o Ysonde Jensen, Joanne Palmer, and Brenda Cornett. These Proceedings would not have been possible without the guidance of the Board of Editors and the untiring help of Pam Houmere and Walter Thorner. Peer review, editing of the many foreign contributions and putting them into a coherent electronic format turned out t o be a major effort. Hans J. Schneider-Muntau vIIthINTERNATIONAL CONFERENCE ON MEGAGAUSS MAGNETIC FIELD GENERATION AND RELATED TOPICS. TALLAHASSEE, FL, USA, OCTOBER 18-23, 1998 This page intentionally left blank INTERNATIONAL STEERING COMMITEE Larry L. Altgilbers - Missile Defense Space Technology Center William L. Baker - Phillips Laboratory Evgenii I. Bichenkov - Lavrentyev Institute of Hydrodynamics/RussianAcademy of Sciences Jay B. Chase - Lawrence Livermore National Laboratory Maynard (Bill) Cowan - Sandia National Laboratories Dennis J. Erickson - Los Alamos National Laboratory C. Max Fowler - Los Alamos National Laboratory James H. Goforth - Los Alamos National Laboratory F. Herlach - Catholic University, Leuven Noboru Miura - Institute for Solid Physics/University of Tokyo Bob Reinovsky - Los Alamos National Laboratory Hans J. Schneider-Muntau - National High Magnetic Field Laboratory Victor D. Selemir - All-Russian Scientif c Research Institute of Experimental Physics Gennady A. Shvetsov - Lavrentyev Institute of Hydrodynamics/RussianAcademy of Sciences Vladimir M. Titov - Lavrentyev Institute of Hydrodynamics/RussianAcademy of Science Peter J. Turchi - The Ohio State University E. P. Velikhov - Kurchatov Institute for Atomic Energy PROGRAM COMMITTEE L. Campbell - Los Alamos National Laboratory R. Clark - University of New South Wales J. Degnan - Air Force Research Laboratory, Phillips Reseach Site, Kirtland AFB P. Frings - Van Der Waals-Zeeman Institute J. Goforth - Los Alamos National Laboratory F. Herlach - Catholic University, Leuven H. Jones - University of Oxford W. Joss - Grenoble High Magnet Field Laboratory K. Kindo - Osaka University A. Lagutin - Kurchatov Institute of Atomic Energy N. Miura - Institute for Solid State Physics N. Popkov - Russian Federal Nuclear Center, All-Russian Scientif c Research Institute of Experimential Physics R. Reinovsky - Los Alamos National Laboratory G.A. Shneerson - St. Petersburg Technical University G. Shvetsov - Lavrentyev Institute of Hydrodynamics R. Spielman - Sandia National Laboratories M. Springford - H.H. Wills Physics Laboratory, University of Bristol P. Turchi - The Ohio State University M. von Ortenberg - Humboldt University, Berlin vIIthINTERNATIONAL CONFERENCE ON MEGAGAUSS MAGNETIC FIELD GENERATION AND RELATED TOPICS. TALLAHASSEE, FL, USA, OCTOBER 18-23, 1998 LOCAL ORGANIZING COMMITTEE Jim Brooks - National High Magnetic Field Laboratory Jack E. Crow - National High Magnetic Field Laboratory James H. Degnan - Phillips Laboratory Lloyd Engel - National High Magnetic Field Laboratory C. Max Fowler - Los Alamos National Laboratory Jerry T. Jones - Air Force Wright Laboratory Daniel A. Matuska - Orlando Technology, Inc. Bob Reinovsky - Los Alamos National Laboratory Dwight Rickel - Los Alamos National Laboratory Alita Roach - Los Alamos National Laboratory Hans J. Schneider-Muntau - National High Magnetic Field Laboratory Rick 6 . Spielman - Sandia National Laboratories SPONSORING ORGANIZATIONS Los Alamos National Laboratory Sandia National Laboratories Air Force Research Laboratory, Phillips Site, Kirtland AFB National High Magnetic Field Laboratory Megagauss Institute Russian Federal Nuclear Center, All-Russian Scientific Research Institute of Experimental Physics Oxford Instruments Keithley Instruments F.W. Bell, Division of Bell Technologies GMW Associates Lakeshore Cryotronics Janis Research Co. Leon County Tourist Development Council Megagauss Magnetic Field Generation, i t s A p p l i c a t i o n t o S c i e n c e a n d U l t righ a - HPulsed-Power igh Pulsed-P ower Technology Technology TABLE OF CONTENTS OVERVIEWS AND LECTURES ADVANCED HIGH EXPLOSIVE PULSED POWER TECHNOLOGY AT VNllEF 1 1 V. K. CHERNYSHEV THE DIRAC EXPERIMENTS - RESULTS AND CHALLENGES R. G. CLARK, J. L. O’BRIEN, A. 5. DZURAK, B. E. KANE, N. E. LUMPKIN, 12 D. J. RNLLEY, R. I? STARRETT; 0. G. RICKEL, J. D. GOETEE, L. J. CAMPBELL, C. M. FOWLER, C. MIELKE, N. HARRISON, W. D. ZERWEKH, D. CLARK, B. D. BARTRAM, J. C. KING, D. PARKIN, H. NAKAGXVIIAWA, and N. MIURA EXPLOSIVE FLUX COMPRESSION: 50 YEARS OF LOS A M O S ACTIVITIES 22 C. FOWLER, D. THOMSON, and W. GARN A REVIEW OF U. S. HIGH EXPLOSIVE PULSED POWER SYSTEMS 29 J. H. GOFORTH MEGAGAUSS FIELDS FROM FORTY YEARS AGO INTO THE NEXT CENTURY F: HERLACH THEORIES OF HIGH TEMPERATURE SUPERCONDUCTIVITY 34 39 J. R. SCHRIEFFER INVESTIGATIONS OF FLUX COMPRESSION ENERGY SOURCES AND ULTRA-HIGH MAGNETIC FIELD GENERATORS IN VNllEF 46 V. D. SELEMIR, and V. A. DEMIDOV ELECTROMAGNETIC LAUNCH - STATE OF THE ART AND OPPORTUNITIES 55 G. A. SHVETSOV GENERATION OF MEGAGAUSS MAGNETIC FIELDS Ultra - Hi3h Magnetic Fields MORE THAN 20 MG MAGNETIC FIELD GENERATION IN THE CASCADE MAGNETOCUMULATIVE MC-1 GENERATOR 61 61 B. A. BOYKO, A. 1. BYKOV, M. 1. DOLOTENKO, N. I? KOLOKOL‘CHIKOV, 1. M. M A R K M S N , 0. M. TATSENKO, and A. M. SHUVALOV ULTRA-HIGH MAGNETIC FIELDS GENERATION USING A DISK FLUX COMPRESSION GENERATOR OF ENERGY 67 V. D. SELEMIR, V. A. DEMIDOV, A. A. KARPIKOV, YU. V. VLASOV, 5. A. KAZAKOV, and N. P. KOLOKOLCHIKOV MULTIPLE-TURN MAGNETOCUMULATIVE GENERATOR 71 A. J. KARTELEV and V. K. CHERNYSHN GENERATION OF MEGAGAUSS MAGNETIC FIELDS BY INITIATION AND GROWTH OF MHD INSTABILITIES I? 75 1. ZUBKOV and K. A. TEN INVESTIGATION OF EFFECTIVENESS OF MC-1 GENERATOR CASCADES MATERIAL MADE FROM POWDER COMPOSITE 80 V. V. ASENA, B. A. BOYKO, A. 1. BYKOV, M. 1. DOLOTENKO, N. I? KOLOKOL’CHIKOV, 0. M. TATSENKO, and V. 1. TIMARNA GENERATION OF MEGAGAUSS MAGNETIC FIELDS Non-Destructive High Magnetic FieldsIConductor Development MEGAGAUSS FIELDS DURING MILLISECONDS L. J. CAMPBELL, D. EMBURY, K. HAN, D. M. PARKIN, A. G. BACA, K. H. KIHARA, J. R. SIMS, G. BOEBINGER, Y. EYSSA, B. LESCH, L. LI, J. SCHILLIG, H. J. SCHNEIDER-MUNTAU, and R. WALSH vIIthINTERNATIONAL CONFERENCE ON MEGAGAUSS MAGNETIC FIELD GENERATION AND RELATED TOPICS. TALLAHASSEE, FL, USA, OCTOBER 18-23, 1998 85 85 PULSED POWER SUPPLY BASED ON MAGNETIC ENERGY STORAGE FOR NON-DESTRUCTIVE HIGH FIELD MAGNETS G. AUBERT; 5. DEFOUG, W. JOSS, F! SALA, M. DUBOIS, and V. KUCHINSK HIGH FIELD PULSED MAGNETS FOR CHARACTERISATION OF TECHNICAL HIGH TEMPERATURE SUPERCONDUCTORS F! M. SALEH, D. T: RYAN, and H. JONES GENERATION OF MEGAGAUSS FIELDS IN INDESTRUCTIBLE SOLENOIDS WITH QUASI-FORCE-FREE WINDINGS 91 95 99 G. A. SHNEERSON, E. L. AMROMIN, V. % KHOZIKOV, and A. 1. BOROVKOV SPATIAL MULTI-TURN STRUCTURE OF FLAT SHEETS FOR MEGAGAUSS MAGNETIC FIELD GENERATION 1. P. EFIMOV, 5. 1. KRIVOSHEYEV, and G. A. SHNEERSON OPTIMAL USE OF MAGNETIC ENERGY IN A MAGNET R. KRATZ, % M . EYSSA, L. LI, H. J. SCHNEIDER-MUNTAU, M. R. VAGHAR, a n d 5. W. VAN SCIVER I-, 2- AND N-COIL SYSTEMS 108 112 116 R. KRATZ, % M . EYSSA, L. LI, H. J. SCHNEIDER-MUNTAU, M. R. VAGHAR, a n d 5. W. VAN SCIVER THE CONSTRUCTION OF HIGH PERFORMANCE PULSE MAGNETS AT NHMFL B. LESCH, b! COCHRAN, L. LI, F! PERNAMBUCO WISE, 5. TOZER, 120 H. J. SCHNEIDER-MUNTAU, a n d 5. VAN SCIVER DESIGN OF A 90 T PULSE MAGNET 124 M . R. VAGHAR, L. LI, % EYSSA, H. J. SCHNEIDER-MUNJAU, a n d R. KRATZ HIGH FIELD PULSE MAGNETS WITH NEW MATERIALS 128 L. LI, B. LESCH, V. G. COCHRAN, % EYSSA, 5. JOZER, C. H. MIELKE, D. RICKEL, 5. W. VAN SCIVER, and H. J. SCHNEIDER-MUNJAU NEW CONDUCTORS FOR MAGNETS 5. ASKENAZY , F: LECOUTURIER, L. THILLY, a n d G. COFFE INVESTIGATION, DEVELOPMENT AND MANUFACTURE OF HIGH STRENGTH, HIGH CONDUCTIVITY CUlSS WIRE FOR LARGE SCALE MAGNETS b! PANTSYRNYI, A. SHIKOV, A. NIKULIN, G. VEDERNIKOV, 1. GUBKIN, 132 141 and N. SALUNIN A SURVEY OF PROCESSING METHODS FOR HIGH STRENGTH-HIGH CONDUCTIVITY WIRES FOR HIGH FIELD MAGNET APPLICATIONS 147 J. D. EMBURY a n d K. HAN INTERNAL STRESSES IN WIRES FOR HIGH FIELD MAGNETS K. HAN, J. D. EMBURY, A. C. LAWSON, R. B. VON DREELE, J. T: WOOD, 154 a n d J. W. RICHARDSON, JR. FABRICATION ROUTES FOR HIGH STRENGTH-HIGH CONDUCTIVITY WIRES J. D. EMBURY, K. HAN, J. R. SIMS, J. % COULTER, V. 1. PANTSYRNYI, 158 A. SHIKOV, and A. A. BOCHVAR GENERATION OF MEGAGAUSS MAGNETIC FIELDS High Maqnetic Fields in Small Volumes GIGAGAUSS MAGNETIC FIELD GENERATION FROM HIGH INTENSITY LASER SOLID INTERACTIONS J. SEFCIK, M. D. PERRY, B. F: LASINSKI, A. B. LANGDON, 5: COWAN, J. HAMMER, 5. HATCHET, A. HUNT, M. H. KEY, M . MORAN, D. PENNINGTON, R. SNAVELY, J. TREBES, a n d 5. C. WlLKS MesagaussMagnetic Field Generation, i t s Application t o Science and Ultra-High Pulsed-PowerTechnology 161 161 ELECTRICAL AND THERMAL PROPERTIES OF MICROELECTROMAGNETS FOR ATOM MANIPULATION M. DRNDIC, K. 5. JOHNSON, M. PRENTISS, and R. M. WESTERVELT NONDESTRUCTIVE MINI-COILS APPROACHING MEGAGAUSS FIELDS 167 171 M. VON ORTENBERG and H.-U. MUELLER MAGNETO-OPTIC MEASUREMENTS UP TO 50 T USING MICRO-COILS 175 K. MACKAY, M. BONFIM, D. GIVORD, A. FONTAINE, and J. C. PEUZIN FEASIBILITY OF MICRO-COILS 179 L. LI, H. J. SCHNEIDER-MUNTAU, 5. WIRTH, V. NEU, I? XIONG, and 5. VON MOLNAR MICRO-MAGNETS E HERLACH, A. VOLODIN, and C. VAN HAESENDONCK EARLY ATEMPTS AT MINI (SUPERCONDUCTING) MAGNETS - ON THE WAY TO MICRO MAGNETS? 185 188 H. JONES HIGH TEMPERATURE SUPERCONDUCTING THIN FILM MAGNETS Y. 5. HASCICEK, Y. EYSSA, 5. W. VAN SCIVER, and H. J. SCHNEIDER-MUNTAU SCIENCE IN MEGAGAUSS MAGNETIC FIELDS PHYSICAL PROCESSES IN DYNAMIC MAGNETIC FIELDS TO 800 T J. 5. BROOKS, J. COTHERN, J. A. SIMMONS, M. J. HAFICH, W. LEWIS, 5. GALLEGOS, D. DEVORE, B. MARSHALL, M. GROVER, G. LEACH, 191 195 195 C. H. MIELKE, D. RICKEL, J. D. GOElTEE, D. CLARK, M. FOWLER, J. KING, L. TABAKA, J. DETWILER, E. C. CLARK, 0. TATSENKO. V. PLATONOV, A. BYKOV, C. LANDEE, and M. TURNBULL MAGNETIC SYSTEMS IN MEGAGAUSS MAGNETIC FIELDS: ~, RESULTS OF DIRAC AND KAPITSA EXPERIMENTS 207 0. M. TATSENKO and V. D. SELEMIR OVERVIEW OF THE 1997 DIRAC HIGH-MAGNETIC-FIELD-EXPERIMENT SERIES AT LOS ALAMOS 21 3 D. A. CLARK, L. J. CAMPBELL, K. C. FORMAN, C. M. FOWLER, J. D. GOETEE, C. H. MIELKE, D. G. RICKEL, and B. R. MARSHALL QUANTUM TRANSFORMATIONS OF Fe8 MAGNETIC NANOCLUSTERS IN MEGAGAUSS MAGNETIC FIELDS A. 1. BYKOV, M. 1. DOLOTENKO, A. V. FILIPPOV, N. I? KOLOKOL’CHIKOV, 217 V. V. PLATONOV, 0. M. TATSENKO, 1. A. LUBASHEVSKY, A. A. MUKHIN, G. G. MUSAEV, V. 1. PLIS, A. 1. POPOV, V. D. SELEMIR, and A. K. ZVEZDIN SPIN-FLIP TRANSITION AND FARADAY EFFECT IN MnFz IN MEGAGAUSS MAGNETIC FIELD 221 V. V. PLATONOV, 0. M. TATSENKO, D. A. CLARK, C. M. FOWLER, J. D. GOElTEE, D. G. RICKEL, W. LEWIS, B. MARSHALL, A. A. MUKHIN, V. 1. PLIS, A. I. POPOV, and A. K. ZVEZDIN NANO-SCALE FERRIMAGNET MnlzAc IN MEGAGAUSS MAGNETIC FIELD 22s V. V. PLATONOV, 0. M. TATSENKO, A. 1. BYKOV, D. A. CLARK, C. M. FOWLER, J. D. GOEITEE, D. G. RICKEL, A. K. ZVEZDIN, A. A. MUKHIN, 1. A. LUBASHEVSKY, V. 1. PLIS, A. 1. POPOV, B. BARBARA, A. CANESCHI, D. GAlTESCHI, and R. SESSOLI INVESTIGATION OF LEVEL CROSSING EFFECT IN RARE-EARTH PARAMAGNETICS IN ULTRA-HIGH MAGNETIC FIELDS UP TO 500 T V. V. PLATONOV, 0. M. TATSENKO, 1. M. MARKEVTSEV, M. ?t MONAKHOV, 2. A. KAZEI, R. 2. LEVITIN, N. I? KOLMAKOVA, and A. A. SIDORENKO Vlllth INTERNATIONAL CONFERENCEON MEGAGAUSSMAGNETIC FIELD GENERATION AND RELATED TOPICS Tallahassee, FL, USA, October 18-23,1998 230 BAND CALCULATION STUDY OF METAMAGNETIC TRANSITIONS OF FeSi IN MEGAGAUSS FIELD H. OHTA, 7: ARIOKA, E. KULATOV, S. HALILOV, and L. VINOKUROVA ISENTROPIC COMPRESSION OF ARGON AND KRYPTON USING AN MC-1 FLUX COMPRESSION GENERATOR 233 237 L. VEESER, C. EKDAHL, H. OONA, I? RODRIGUEZ, G. SCHMln, J. SOLEM, 5. YOUNGER, 5. BAKER, C. HUDSON, W. LEWIS, 6. MARSHALL, W. TURLU, A. EYKOV, G. EORISKOK M. DOLOTENKO, N. EGOROV, N. KOLOKOL’CHIKOV, M. KOZLOV, K KUROPATKIN, and A. VOLKOV HIGH SENSITIVITY MEGAGAUSS SPECTROSCOPY 241 N. PUHLMANN, 1. STOLPE, H . 4 . MULLER, 0. PORTUGALL, and M. VON ORTENEERG EIGENSTATES OF BLOCH ELECTRONS IN A HIGH MAGNETIC FIELD: OPTICAL PROPERTIES 244 Y. YA. DEMIKHOVSKII, A. A. PEROV, and D. Y. KHOMITSKY CYCLOTRON RESONANCE MEASUREMENT OF BEDT-lTF SALT UNDER HIGH MAGNETIC FIELD H. OHTA, K OSHIMA, K. AKIOKA, 5. OKUEO, and K. KANODA MAGNETO-RESISTANCE OF La0,67Ca~,~,MnO, FILMS IN PULSED HIGH MAGNETIC FIELDS 5. S A L N I ~ I U S ,B. VENGALIS, F: ANISIMOVAS, J. NOVICKIJ, R. TOLUTIS, 250 254 0. KIPRIJANOVIC, J. NOVICKIJ, and L. ALTGILEERS MAGNETIZATION OF AN 5 = 112 AND 1 FERRIMAGNETIC CHAIN N i C ~ ( p b a ) ( D ~ 0 ) ~ 2 D IN~ HIGH O MAGNETIC FIELDS M. HAGIWARA, K 259 NARUMI, K. TATANI, K. KINDO, and K. MlNAMl MAGNETIZATION AND MAGNETORESISTANCE MEASUREMENTS UP TO 60 T AT 70 mK 262 K NARUMI, N. TAKAMOTO, K. KINDO, T. C. KOBAYASHI, N. SHIMIZU, F: IGA, 5. HIURA, T. TAUEATAKE, and M. VERDAGUER MAGNETIZATION CURVES AND MAGNETIC PHASE TRANSITIONS OF NEW ISING FERRIMAGNETS A. S. LAGUTIN, G. E. FEDOROV, J. VANACKEN, and F: HERUCH HIGH FIELD MAGNETIZATION PROCESSES OF 5 = 1 ANTIFERROMAGNETIC CHAINS WITH BOND ALTERNATION M. HAGIWARA, K NARUMI, K. KINDO, R. SATO, H. NAKANO, M. KOHNO, 266 2 70 and M. TAKAHASHI COMPRESSION OF METALS UNDER INTENSE SHOCK WAVES 274 R. F: TRUNIN PLASMAS, MAGNETIZED PLASMAS, FUSION FUSION IN MAGNETICALLY COMPRESSED TARGETS 28 1 281 K N. MOKHOV MAGNETIZED TARGET FUSION (MTF): A LOW-COST FUSION DEVELOPMENT PATH 289 1. R. LINDEMUTH, R. E. SIEMON, R. C. KIRKPATRICK, and R. E. REINOVSKY INITIAL EXPERIMENTS WITH THE PLASMA CHAMBERS MAGO, HAVING NO CENTRAL CURRENT-CARRYING POST IN THE PLASMA HEATING COMPARTMENT 294 A. A. EAZANOV, and N. 1. POZDOV NUMERICAL SIMULATION OF MAGOIMTF CHAMBER OPERATION AND COMPARISON OF COMPUTED DATA WITH SOME EXPERIMENTS A. A. EAZANOV, 5. E GARANIN, 5. D. KUZNETSOV, Y. 1. MAMYSHN, Y. N. MOKHOV, A. N. SUEEOTIN, and Y. 6. YAKUEOV Megagauss Magnetic Field Generation, its Application to Science and Ultra-High Pulsed-Power Technology 298 THE ROLE OF DRIFTS IN MAGNETIZED PLASMA OF THE MAG0 SYSTEM 5. F: GARANIN CHARACTERIZATION OF A TARGET PLASMA FOR MTF 302 305 F: J. WYSOCKI, J. M. TACCE7T1, G. IDZOREK, H. OONA, R. C. KIRKPATRICK, 1. R. LINDEMUTH, F! 7: SHEEHEY, and K C. E THlO MODELING OF PRESENT AND PROPOSED MAGNETIZED TARGET FUSION EXPERIMENTS 309 P. SHEEHEY, R. FAEHL, R. KIRKPATRICK, and 1. LINDEMUTH MEASUREMENTS OF DENSE PLASMA PARAMETERS BY THE INTERACTION OF PLASMA WITH STRONG MAGNETIC FIELD V. B. MINTSEV, 5. V. DUDIN, V. K. GRYAZNOV, A. E. USHNURTSN, N. 5. SHILKIN, and V. E. FORTOV THE STABILITY OF QUASI-ADIABATIC PLASMA COMPRESSION BY A LONGITUDINAL MAGNETIC FIELD 312 316 V. F: YERMOLOVICH, A. 1. IVANOVSKY, K 1. KARELIN, A. I? ORLOV, and V. D. SELEMIR PERPENDICULAR SHOCK WAVE STRUCTURE IN COLD COLLISIONLESS PLASMA CONSISTING OF TWO ION SPECIES 0. M. BURENKOV, and 5. F: GARANIN PLASMA HEATING AND EXPANSION IN ELECTRICAL EXPLOSION OF A CONDUCTOR IN STRONG MAGNETIC FIELD K E. ADAMIAN, V. M. VAS/LEVSKlY, 5. N. KOLGATIN, 320 324 and G. A. SHNEERSON INTERACTION OF BOUNDARY MATERIAL WITH MAGNETIZED PLASMA 328 J. H. DEGNAN, G. E K I U T U , B. B. KREH, R. E. PETERKIN, JR, N. F: RODERICK, E. L. RUDEN, K. E STEPHENS 11, I? J. TURCHI, 5. K. COFFEY, M. H. FRESE, D. G. GALE, J. D. GRAHAM, D. MORGAN and D. P L A m IMPLODING LINERS FOR CONTROLLED FUSION: SOME LESSONS LEARNED 334 I? J. TURCHI RAILGUNS, LAUNCHERS, AND RELATED TOPICS HYPERVELOCITY RAILGUN: THE OPTIMAL SOLUTIONS V. E. OSTASHEV, E. F: LEBEDEV, and K E. FORTOV CRYOGENIC LAUNCHER EXPERIMENTS: THE QUEST FOR A VERY HIGH EFFICIENCY 337 337 341 B. M. NOVAC, M. C. ENACHE, t? SENIOR, 1. R. SMITH, and K. GREGORY THEORETICAL AND EXPERIMENTAL INVESTIGATION OF MAGNETIC-IMPULSE PLATE ACCELERATION A. V. BABKIN, 5. V. FEDOROV, 5. V. LADOV, V. A. GRIGORYAN, 345 V. A. KRUZHKOV, and A.V. SHERBAKOV BEHAVIOR OF METALLIC SHAPED-CHARGE JETS UNDER THE ACTION OF A CURRENT PULSE 349 G. A. SHVETSOV, A. D. MATROSOV, A. V. BABKIN, 5. V. LADOV, and 5. V. FEDOROV FEATURES OF METAL SHAPED CHARGE JET DEFORMATION IN LONGITUDINAL LOW-FREQUENCY MAGNETIC FIELD 5. V. FEDOROV, A. V. BABKIN, 5. V. LADOV, and V. M. MARlNlN vIIthINTERNATIONAL CONFERENCE ON MEGAGAUSS MAGNETIC FIELD GENERATION ANDRELATEDTOPICS RELATED TOPICS.Tallahasse TALLAHASSEE, FL, USA, OCTOBER 18-23, 1998 AND . 353 EXPLOSIVE ULTRA-HIGH PULSED POWER GENERATORS ANALYSIS OF THE DISK EXPLOSIVE MAGNETIC GENERATOR OPERATION IN THE HEL-1 EXPERIMENT V. A. A. A. A. R. 357 357 K. CHERNYSHEV, V. N. MOKHOV, V. N. BUSIN, 0. M. BURENKOV, M. BUYKO, V. V. VAKHRUSHEV, B. E. GRINEVICH, YU. 1. GORBACHEV, 1. KUZAEV, A. 1. KUCHEROV, V. 1. MAMYSHEV, YU. 1. MATSEV, A. PETRUKHIN, A. 1. PISCHUROV, A. 1. STARTSEV, V. B. YAKUBOV, G. ANDERSON, C. A. EKDAHL, D. CLARK, 1. R. LINDEMUTH, E. REINOVSKY, R. FAEHL, a n d 5. M. YOUNGER 1.3 MV VOLTAGE PULSE FORMATION ON 13 OHM RESISTOR WITH MCG- 160 A. 5. KRAVCHENKO, A. 5. BORISKIN, YU. V. VILKOV, V. D. SELEMIR, YE. M . DIMANT, A. 5. YURYZHN, D. 1. ZENKOV, A. A. TKACHUK, 361 YE. N. KIRSHANOVA, M. B. KOZLOV, a n d T. BOUET TRANSFORMER EXPLOSIVE MAGNETIC GENERATOR 364 A. JA. KARTELEV and V. K. CHERNYSHEV HIGH-VOLTAGE POWER SOURCE ON THE BASIS OF MAGNETOCUMULATIVE GENERATOR OF THE TYPE EMG-80 A. 5. BORISKIN, YE. M. DIMANT, V. D. SELEMIR, a n d A. A. SOLOV’YEV AUTONOMOUS MAGNETOEXPLOSIVE GENERATOR OF MEGAVOLT, 100 NS PULSES 367 371 V. YE. GURIN, V. N. KATAEV, P V. KOROLEV, V. 1. KARGIN, G. F: MAKARTSEV, V. N. NUDIKOV, A. 5. PIKAR, N. F: POPKOV, and A. F: SARATOV HIGH VOLTAGE PULSED MCG-BASED ENERGY SOURCE 376 E. V. CHERNYKH, V. E. FORTOV, K. V. GORBACHEV, E. V. NESTEROV, 5. A. ROSCHUPKIN, a n d V. A. STROGANOV THE OUTPUT CHARACTERISTICS OF A TWO-STAGED EXPLOSIVE MAGNETIC COMPRESSION GENERATOR WITH HIGH INDUCTIVE LOAD X. G. GONG, C. W. SUN, W. P XIE, Q. Z. SUN, a n d Z. F: LIU ON THE DEVELOPMENT OF MCG WITH ARMATURE, ASSEMBLED FROM SEPARATE TUBES 380 386 L. N. PLYASHKEVICH TWO-STAGED MAGNETOCUMULATIVE GENERATORS FOR HIGH IMPEDANCE LOADS A. E. USHNURTSEV, 5. V. DUDIN, V. B. MINTSEV, V. E. FORTOV, V. E. OSTASHEV, A. A. ULYANOV, E. F: LEBEDEV, A. A. LEONTYEV, 390 a n d A .V. SHURUPOV CLASSIFICATION OF HELICAL FLUX-COMPRESSION GENERATORS 394 B. M . NOVAC a n d 1. R. SMITH AUTONOMOUS ENERGY SOURCE ON THE BASIS OF HELICAL MCG WITH SIMULTANEOUS HE-CHARGE INITIATION ON THE AXIS A. 5. KRAVCHENKO, YU. V. VILKOV, A. 5. YURYZHN, M . M . SAITKULOV, 401 a n d 1. M . BRUSNlGlN EXPERIMENTAL INVESTIGATION OF OPERATION OF HELICAL GENERATOR WITH TRANSFORMER ENERGY OUTPUT A. 5. KRAVCHENKO, A. 5. BORISKIN, YU. V. VILKOV, YE. M. DIMANT, A. 1. KARPOV, 5. T: NAZARENKO, V. 5. PAVLOV, and M. B. KOZLOV Megagauss Magnetic Field Generation, i t s Application to Science and Ultra-Hiph Pulsed-Power Technology 404 COMPACT HELICAL MAGNETOCUMULATIVE GENERATOR FOR THE FORMATION OF POWERFUL HIGH-VOLTAGE ENERGY PULSES A. 5. KRAVCHENKO, V. D. SELEMIR, A. 5. BORISKIN, YU. V. VILKOV, 407 YE. M. DIMANT, and A. 6. YERMAKOV ONE APPROACH TO SELECTING THE MAIN PARAMETERS OF THE EMG HELICAL COIL V. K. CHERNYSHEV and B. 7: YEGORYCHEV HELICAL EMG EFFECTIVE RESISTANCE 41 1 414 V. K. CHERNYSHEV, E. 1. ZHARINOV, V. N. BUSIN, B. E. GRINEVICH, 0. V. SOKOLOVA, G. N. SMIRNOVA, and K. N. KLlMUSHKlN INVESTIGATION OF MAGNETO-PLASMA COMPRESSOR OPERATION POWERED FROM A HELICAL FLUX COMPRESSION GENERATOR 5. N. GOLOSOV, YU. V. VLASOV, V. A. DEMIDOV, and 5. A. KAZAKOV HELICAL EXPLOSIVE FLUX COMPRESSION GENERATOR RESEARCH AT THE AIR FORCE RESEARCH LABORATORY 418 422 M. LEHR, D. CHAMA, J. DEGNAN, G. KIUlTU, O T CAVAZOS, D. GALE, f? PELLITIER, W. SOMMARS, 5. COFFEY, L. BAMERT, and K. BELL SIMULATION, DESIGN AND CONSTRUCTION OF A PULSED POWER SUPPLY FOR HIGH POWER MICROWAVES USING EXPLOSIVELY DRIVEN MAGNETIC FLUX COMPRESSION 425 M. KRISTIANSEN, J. DICKENS, M. GIESSELMANN, E. KRISTIANSEN, and 7: HURTIG GENERATING MICROWAVE RADIATION PULSES WITH MCG 429 A. G. ZHERLITSYN, G. G. KANAEV, G. V. MELNIKOV, V. TSVETKOV, A. E. USHNURTSEV, 5. V. DUDIN, V. B. MINTSEV, and V. E. FORTOV CONSIDERATIONS OF AN AUTONOMOUS COMPACT SOURCE FOR HIGH POWER MICROWAVE APPLICATIONS B. M. NOVAC and 1. R. SMITH COMPACT EXPLOSIVE DRIVEN SOURCES OF MICROWAVES: TEST RESULTS 432 438 L. ALTGILBERS, 1. MERRIn, M. BROWN, J. HENDERSON, D. HOLDER, A. VERMA, M. J. HOEBERLING, R. F: HOEBERLING, G. CARP, W. FENNER, C. M. FOWLER, J. PINA, and M. LEWIS EXPLOSIVE DEVICE FOR GENERATION OF PULSED FLUXES OF SOFT X-RAY RADIATION V. D. SELEMIR, V. A. DEMIDOV, A. V. IVANOVSKY, 446 V. F: YERMOLOVICH, V. G. KORNILOV, V. 1. CHELPANOV, S. A. KAZAKOV, Y. V. VLASOV, and A. I? ORLOV SHOCK COMPRESSION OF MAGNETIC FIELDS IN Csl 450 I? TRACY, L. L. ALTGILBERS, 1. M E R R l n and M. BROWN EXPLOSIVE MHD GENERATORS 458 E. F: LEBEDEV, V. E. OSTASHEV and K E. FORTOV OPTIMIZING THE RANCHERO COAXIAL FLUX COMPRESSION GENERATOR D. G. TASKER, J. H. GOFORTH, W. L. ATCHISON, C. M. FOWLER, D. H. HERRERA, J. C. KING, 1. R. LINDEMUTH, E. A. LOPEZ, 464 E. C. MARTINEZ, H. OONA, R. E. REINOVSKY, J. STOKES, L. J. TABAKA, D. T. TORRES, and f? J. MILLER ENERGY CONVERSION EFFICIENCY OF MCG-BASED LIGHTNING SIMULATORS E. V. CHERNYKH, V. E. FORTOV, K. V. GORBACHEV, 1. I? KUJEKIN, E. V. NESTEROV, V. A. STROGANOV, YU. A. KARPOUSHIN, and A. V. SHOURUPOV Vlllth INTERNATIONALCONFERENCE ON MEGAGAUSS MAGNETIC FIELD GENERATION AND RELATEDTOPICS Tallahassee, FL, USA, October 18-23, 1998 468 IMPLODING LINERS STABILITY OF MAGNETICALLY IMPLODED LINERS FOR HIGH ENERGY DENSITY EXPERIMENTS 473 473 R. REINOVSKY, W. ANDERSON, W. ATCHISON, R. BARTSCH, D. CLARK, C. EKDAHL, R. FAEHL, J. GOFORTH, R. KEINIGS, 1. LINDEMUTH, D. MORGAN, G. RODRIGUEZ, J. SHLACHTER, and 0. TASKER INSTABILITY GROWTH OF MAGNETICALLY IMPLODED CYLINDRICAL ALUMINUM AND HIGH-STRENGTH ALUMINUM ALLOY LINERS A. M. BUYKO, 0. M. BURENKOV, 5. F: GARANIN, YU. N. GORBACHN, B. E. GRINEVICH, V. V. ZMUSHKO, G. G. IVANOVA, A. 1. KUZYAYN, 479 V. N. MOKHOV, I? N. NIZOVTSEV, A. A. PETRUKHIN, A. 1. PISHCHUROV, V. P. SOLOVYEV, V. N. SOFRONOV, V. K. CHERNYSHEV, V. B. YAKUBOV. B. G. ANDERSON, W. E. ANDERSON, W. L. ATCHISON, R. R. BARTSCH, W. BROSTIE, J. COCHRANE, C. A. EKDAHL, R. FAEHL, 1. R. LINDEMUTH, D. V. MORGAN, H. OONA, R. E. REINOVSKY, J. STOKES, L. C. TABAKA, and 5. M. YOUNGER STUDIES OF SOLID LINER INSTABILITY DURING MAGNETIC IMPLOSION 482 W. ATCHISON, R. FAEHL, and R. RElNOVSKY HYDRODYNAMIC LINER EXPERIMENTS USING THE RANCHERO FLUX COMPRESSION GENERATOR SYSTEM 485 J. H. GOFORTH, W L. ATCHISON, C. M. FOWLER, D. H. HERRERA, J. C. KING, E. A. LOPEZ, H. OONA, R. E. REINOVSKY, J. L. STOKES, L. J. TABAKA, 0. G. JASKER, D. T: TORRES, F; C. SENA, J. A. MCGUIRE, 1. R. LINDEMUTH, R. J. FAEHL, R. K. KEINIGS, 0. F; GARCIA, and B. BROSTE LINER STABILITY EXPERIMENTS AT PEGASUS: DIAGNOSTICS AND EXPERIMENTAL RESULTS 489 D. A. CLARK, D. V. MORGAN, and G. RODRIGUEZ IMPLODING LINER MATERIAL STRENGTH MEASUREMENTS AT HIGH-STRAIN AND HIGH-STRAIN RATE 493 R. BARTSCH, H. LEE, 0. HOLTKAMe 6. WRIGHT, J. STOKES, D. MORGAN, W. ANDERSON, and W. BROSTE Z AND &CURRENT GEOMETRY FEATURES OF METALLIC TUBES COMPRESSION IN PULSED HIGH MAGNETIC FIELDS TO STUDY CONSTITUTIVE RELATIONS AT HIGH STRAIN RATE 497 Y. A. ALEXEEV, M. N. KAZEEV, and J. PETIT MAGNETIC IMPLOSION FOR NOVEL STRENGTH MEASUREMENTS AT HIGH STRAIN RATES 501 H. LEE, D. L. PRESTON, R. R. BARTSCH, R. L. BOWERS, D. HOLTKAMR and B. L. WRIGHT AN EVALUATION OF THE LOS ALAMOS PRECISION AUTOMATED TURNING SYSTEM (PATS) AS A PRODUCTION TOOL FOR ATLAS LINERS 505 W. ANDERSON, R. DAY, D. HATCH, R. GORE, D. MACHEN, J. BARJOS, M. SALAZAR, and I? HANNAH FABRICATION PROCESS FOR MACHINED AND SHRINK-FITTED IMPACTOR-TYPE LINERS FOR THE LOS ALAMOS HEDP PROGRAM B. RANDOLPH FABRICATION OF HIGH ENERGY DENSITY PHYSICS LOADS M. A. SALAZAR, W. ANDERSON, E. ARMIJO, and F; GARCIA Megagauss Magnetic Field Generation, its Application to Science and Ultra-High Pulsed-Power igh Pulsed-Power Technology Technology 508 512 CODES, ANALYSIS, SIMULATIONS CAGEN: A MODERN, PC BASED COMPUTER MODELING TOOL FOR EXPLOSIVE MCG GENERATORS AND ATACHED LOADS J. B. CHASE, D. CHATO, G. PETERSON, P. PINCOSY, 515 515 and G. F: KIUTTU AN INTEGRATED SOFWARE PACKAGE FOR THE DESIGN OF HIGH PERFORMANCE PULSED MAGNETS 521 J. VANACKEN, LI LIANG, L. TRAPPENIERS, K. ROSSEEL, W. BOON, and F: HERLACH NUMERICAL SIMULATION OF OPERATION OF MAGNETOCUMULATIVE GENERATORS WITH HIGH ENERGY GAIN A. 5. KRAVCHENKO and YU. V. VILKOV A FIELD-THEORY APPROACH TO MODELING HELICAL FCGS 525 529 C. M. FORTGANG NUMERICAL SIMULATION OF MAGNETIC FLUX COMPRESSION IN HELICAL-CONE MAGNETOEXPLOSIVE GENERATORS YU. N. DERYUGIN, I? V. KOROLN, V. 1. KARGIN, A. 5. PIKAR, 536 N. F: POPKOV, and E. A. RYASLOV SEMI-EMPIRICAL MODEL FOR THE RESISTANCE OF SPIRAL MAGNETOCUMULATIVE GENERATORS 540 L. ALTGILBERS, 1. MERRITT, M. BROWN, and I? TRACY VOLTAGE DISTRIBUTION OVER EMG HELIX WIRES 546 V. R. CHERNYSHN, E. 1. ZHARINOV, V. N. BUZIN, B. E. GRINEVICH, K. N. KLIMUSHKIN, 1. D. KUDELKIN, A. A. BAZANOV, 0. V. SOKOLOVA, M. M. GUBIN, 5. V. PAK, and A. N. SKOBELEV CALCULATION OF THE AUTONOMOUS MC-GENERATOR WITH A PERMANENT MAGNET V. E. GURIN, V. 1. KARGIN, A. 5. PIKAR, N. F: POPKOV, 550 and E. A. RYASLOV 2-D HYDRODYNAMIC FLOWS CALCULATION AT ISENTROPIC SUBSTANCE COMPRESSION WITH ULTRA-HIGH MAGNETIC FIELD PRESSURE 553 V. V. ASENA, G. V. BORISKOV, a n d A . 1. PANOV EXPLOSIVE AXIAL MAGNETIC FLUX COMPRESSION GENERATOR ARMATURE MATERIAL STRENGTH AND COMPRESSION EFFECTS 557 E. L. RUDEN, G. E KIUTTU, R. E. PETERKIN, JR, and J. B. CHASE ON FEASIBILITY OF RAYLEIGH-TAYLOR INSTABILITY MAGNETIC STABILIZATION OF LINER IMPLOSIONS 5. F: GARANIN, 5. D. KUZNETSOV, V. N. MOKHOV, L. V. YAKUBOVA, 563 V. B. YAKUBOV, and C. EKDAHL 2-D INSTABILITY SIMULATION OF MAGNETICALLY DRIVEN CYLINDRICAL ALUMINUM AND ALUMINUM ALLOY LINERS A. M. BUYKO, 5. E GARANIN, V. V. ZMUSHKO, V. N. MOKHOV, 567 I? N. N I Z O V S N , V. F? SOLOVYN, and V. B. YAKUBOV EXPLORING WAYS TO IMPROVE Z-PINCH CALCULATIONS 571 W. MATUSKA, J. AUBREY, R. BOWERS, H. LEE, 0. PETERSON, C. DEENEY, M. DERZON, and T. NASH THE APPLICATION OF 2-D SIMULATIONS TO Z-PINCH EXPERIMENT DESIGN AND ANALYSIS D. L. PETERSON, R. L. BOWERS, W. MATUSKA, G. A. CHANDLER, C. DEENEY, M. 5. DERZON, M. K. MATZEN, R. C. MOCK, T. J. NASH, T. W. L. SANFORD, R. B. SPIELMAN, and K. W. STRUVE Vlllth INTERNATIONAL CONFERENCE ON MEGAGAUSS MAGNETIC FIELD GENERATION AND RELATEDTOPICS Tallahassee, FL, USA, October 18-23, 1998 576 PLASMADYNAMIC SWITCHING AT MEGAGAUSS MAGNETIC FIELD LEVELS F! J. TURCHI MACH2 SIMULATIONS OF THE DECADE PLASMA OPENING SWITCH USING A TEFLON PLASMA 580 589 D. KEEFER and R. RHODES SHOCK-WAVE DRIVEN FLUX COMPRESSION TECHNIQUE 593 E. 1. BICHENKOV ELECTRICAL CONDUCTIVITY OF THE DETONATION PRODUCTS F! 1. ZUBKOV ANALYSIS OF THE SPATIAL VARIATION AND TIME DEPENDENCE OF THE CURRENT DISTRIBUTION IN A SINGLE-TURN COIL FOR MEGAGAUSS FIELDS 599 604 H.-U. MUELLER, 0. PORJUGALL, and M. VON ORJENBERG SWITCHES AND OTHER 609 CURRENT PULSE SHARPENING BY FERROMAGNETIC OPENING SWITCH G. A. SHNEERSON, 1. F! EFIMOV, 5. 1. KRIVOSHEEV, 609 and YU. N. BOTCHAROV OPENING MECHANISMS IN AN EXPLOSIVELY FORMED FUSE OPENING SWITCH D. KEEFER, M. H. FRESE, L. D. MERKLE, R. E. PETERKlN, JR., N. 614 F; RODERICK, and K. F: STEPHENS I1 HIGH VOLTAGE APPLICATIONS OF EXPLOSIVELY FORMED FUSES D. G. TASKER, J. H. GOFORTH, C. M. FOWLER, D. H. HERRERA, J. C. KING, E. A. LOPEZ, E. C. MARTINEZ, H. OONA, 5. P MARSH, 61 9 R. E. REINOVSKY, J. STOKES, L. J. TABAKA, D. T: TORRES, F: C. SENA, G. KIUTTU, and J. DEGNAN HIGH EFFICIENCY CLOSING SWITCHES FOR MEGAMP PULSED CURRENTS 625 P SENIOR and 1. SMlTH FIRST RESULTS OF MULTI-RADIOGRAPHY IN THE EXPERIMENTS WITH MC-1 GENERATOR 629 G. V. BORISKOV, A. 1. BYKOV, M. 1. DOLOJENKO, N. 1. YEGOROV, N. I? KOLOKOL'CHIKOV, YU. F! KUROPATKIN, N. B. LUKYANOV, I! D. MIRONENKO, V. N. PAVLOV, and V. 1. TIMAREVA EXPERIMENTAL INSTALLATION FOR ELECTRODYNAMIC COMPRESSION B. E. FRIDMAN, N. N. KUSTOV, A. G. LEX, and PH. G. RUJBERG GENERATION OF HIGH-POWER SHOCK WAVES ON PIRIT-2 FACILITY M. V. ZHERNOKLETOV, V. 1. KARGIN, D. V. KOJELNIKOV, 633 637 A. V. MELKOZEROV, A. L. MIKHAILOV, A. Y: NAGOVITSIN, N. F: POPKOV, and E. A. RYASLOV STEEL AND GRAPHITE HEATING BY MEGAAMPERE CURRENT PULSES 641 B. E. FRIDMAN, A. G. LEX, 1. F? MAKAREVICH, PH. G. RUTBERG, a n d A . D. RAKHEL A HIGH-VOLTAGE PULSE TRANSFORMER FOR EXPLOSIVE PULSED-POWER DEVICES C. FORJGANG, A. ERICKSON, and J. GOETEE Megagauss Magnetic Field Generation, i t s A p p l i c a t i o n t o S c i e n c e a n d U l tigh ra-H i g h P u l s e d -Technology Power Technology Pulsed-Power 648 1 MV, 20 NS PULSE GENERATOR FOR HIGH-CURRENT MAGNETRON V. 1. KARGIN, A. 5. PIKAR, N. E POPKOV, E. A. RYASLOV, 653 E. B. ABUBAKIROV, N. F: KOVALEV, and M . 1. FUCHS HIGH MAGNETIC FIELD FACILITIES Z: A FAST PULSED POWER GENERATOR FOR ULTRA-HIGH MAGNETIC FIELD GENERATION 657 657 R. B. SPIELMAN, W. A. S N G A R , K. W. STRUVE, J. R. ASAK C. A. HALL, M . A. BERNARD, J. E. BAILEY and D. H. MCDANIEL GENERATION OF MEGAGAUSS FIELDS BY ELCTROMAGNETIC FLUX COMPRESSION AND THE SINGLE-TURN COIL TECHNIQUE AT ISSP N. MIURA, Y. H. MATSUDA, K. UCHIDA, and 5. TODO THE ATLAS PULSED POWER SYSTEM; A DRIVER FOR PRODUCING MULTI-MEGAGAUSS FIELDS 663 671 C. COCHRANE, JR, R. R. BARTSCH, G. A. BENNEU, W. BOWMAN, H. A. DAVIS, C. A. EKDAHL, R. E GRIBBLE, J. KIMERLL; K. E. NIELSEN, W. M. PARSONS, J. D. PAUL, W. SCUDDER, R. J. TRAINOR, M. C. THOMPSON, and R. G. WA77 J. D. H. D. MULTI-MODULE FLUX COMPRESSION ENERGY SOURCE “SPRUT” V. A. DEMIDOV, V. D. SELEMIR, 5. A. KAZAKOV, YU. V. VLASOV, R. M . GARIPOV, a n d A. I? ROMANOV CONVENTIONAL AND EXPLOSIVE PULSED POWER DEVELOPMENT AT TEXAS AEtM UNIVERSITY 676 680 B. FREEMAN, T: FALESKI, 1. HAMILTON, J. ROCK, a n d T: PARISH THE HUMBOLDT HIGH MAGNETIC FIELD CENTER: MEGAGAUSS OPERATION AND RESULTS UP TO 300 TESLA 684 M. VON ORTENBERG, 0. PORTUGALL, N. PUHLMANN, H.-U. MUELLER, 1. STOLPE, and A. KIRSJE THE EUROPEAN 100 T PROTOTYPE PROJECT I? R J. VAN ENGELEN a n d W. JOSS HIGH FIELD LABORATORY DRESDEN 690 694 R. KRATZ THE TOULOUSE 14 MJ CAPACITOR BANK PULSE GENERATOR 5. ASKENAZK L. BENDICHOU, G. COFFE, I? FERRE, J. M . LAGARRIGUE, J. I? LAURENT, F: LECOUTURIER, J. MARQUEZ, 5. MARQUEZ, and D. RICART GENERATION OF HIGH MAGNETIC FIELDS IN THE MEGAGAUSS RANGE AT THE OSAKA FACILITY 697 704 K. KIND0 THE NEW OXFORD HIGH FIELD FACILITY 710 H. JONES AUTHOR INDEX Vlllth INTERNATIONAL CONFERENCE ON MEGAGAUSSMAGNETIC FIELD GENERATION AND RELATEDTOPICS Tallahassee, FL, USA, October 18-23, 1998 7 15 This page intentionally left blank OVERVIEWS AND LECTURES aDVANCED HIGH EXPLOSIVE PULSED POWER TECHNOLOGY AT VNIIEF V. K. CHERNYSHEV All-Russian Research Institute of Experimental Physics, Sarov, Russia The primary purpose of this presentation is to present the possibilities of super high power explosive magnetic energy sources and to demonstrate some of their applications where their use would be most impressive and beneficial. 1 Introduction High-power sources storing 10 to 100 MJ, and capable of generating pulsed currents from 50 to 100 MA in different loads, are required to solve a number of important problems of modem science and technology. Large and costly stationary capacitor bank facilities have been created for these purposes and are being designed and built abroad. There exist the PEGASUS facility in LANL (5 MJ), Shiva star facility in the Phillips Laboratory (10 MJ), ATLAS facility in LANL (36 MJ), JUPITER facility in Sandia (100 MJ), and others. The energy carriers in these facilities are dielectrics in which energy storage is limited to about 100 JA. VNIIEF chose a unique path of experimentation [l-71. In 1951, the academician A. D. Sakharov proposed using an explosive to carry energy, creating energy storage five orders of magnitude greater than previously available. To convert the chemical energy of the explosive into electromagnetic energy, Sakharov proposed using magnetic cumulation, an effect based on compression assisted by the explosion of a conducting contour with a magnetic flux introduced fkom an outside source. The results were very fruitful. In the process of implementing magnetic cumulation, the MC-2 system design proposed by Dr. Sakharov was considerably improved, and the new generation of devices called helical EMGs. Principally new types of explosive systems were created [8-251 based on different operation principles. The research results follow: 1. 2. 3. 2 The "Potok" family of EMGs with record performance were created. New systems of power amplification were created fast opening switches made possible the generation of a current pulse with 70-100 MA amplitude, a 1 ps front of increase and an output voltage of 500 kV. Application of fast-operating superpower helical EMGs and opening switches, in particular, allowed formation of an ionized and magnetized plasma in a volume of 1000 cm3with a temperature of 0.2 to 1 keV and 2 ps lifetime. This plasma is suitable for additional adiabatic compression and achievement of thermonuclear ignition [26-281. Quick-OperatingHelical EMGs The design simplicity and compactness of helical EMGs, as well as their high power and energy characteristics, attracted the attention of both development engineers and users. After the first open publications of papers [ 1,2] dozens of international investigators developed helical EMGs. However, not all were successful. vIIthINTERNATIONAL CONFERENCE ON MEGAGAUSS MAGNETIC FIELD GENERATION AND RELATED TOPICS. TALLAHASSEE, FL, USA, OCTOBER 18-23, 1998 The helical EMG is a very complex 3-D system that seems initially simple. Such a 3-D problem has had neither solution nor expression, theoretically or computationally. Success in its solution depends on the skills of the scientists and development engineers. Under rapid compression of the circuit, when the active resistance may be neglected and the magnetic flux may be considered to be constant, current and energy increase proportionally to the circuit compression ratio K, = L,/ Lo . LoIo = Qo = LrI = Const, If = I, = L f . K,. Ef = ( L f . 42)/2=@:/21,f = Eo .K, Subscripts ‘0’ and ‘f‘ mark the initial and final values of inductance, current, and energy, respectively. It is difficult to conserve magnetic flux in the compression process. There are always flux losses in real constructions (only some part of initial flux may be conserved, q=@,/@.,) because of the geometrical imperfection of the compression contour, the ohmic resistance of the conductor material and the high voltages leading to electrical breakdowns. The current and energy increase less I, = q.Ic>.KL, E, = qz.E ; KL;q, in its turn, largely depends on K,, making it difficult to use this characteristic. The best characteristic of coil operation during the process of magnetic cumulation was proposed by J. Shearer in 1968 . It is the perfection index (“Figure of merit”), determined from the expression F(t) = - (i/I)(L/L). The high-power helical EMGs developed in the Electrophysical Department at VNIIEF are comparable in energy with the largest US capacitor bank facilities and have been used successfully in Russia, the USA and France to solve a variety of scientific problems. 3 Plasma Focus Powering By Helical EMG Raises Neutron Yield And Makes The Entire System Transportable The chamber using plasma focus was suggested and developed by N. V. Filippov and T. I. Filippova in 1955  and was later refined in many countries [31-401. A French article published in 1971 noted that when an EMG with 0.7-1.0 MA current powered a plasma focus chamber (filled with D-D mixture), a yield of 1.5x109neutrons/pulseat 2.5 MeV was recorded . Later, information surfaced that research on PF type discharges using the EMG was done in the United States [34,37-391. This research occurred simultaneously at VNIIEF. In 1986, a Russian article was published announcing that a small EMG with an opening switch at a discharge current of -400 kA produced a neutron yield of -3.10’O rdpls . In that experiment, the influence of the rate of current increase on plasma shell dynamics and neutron pulse parameters was studied in the gas discharge chambers, which were analogous to the Filippovs’ chambers. These chambers were filled with a 1:1 mixture of deuterium and tritium within the pressure range of 5-20 tor. The experiments showed that, in the plasma focus chambers, application of the EMG resulted in a neutron yield 3-4 times higher than the use of a capacitor source at approximately the same discharge current. This occurred because the current rise rate was increased by 2.5-3 times in the EMG compared to an ordinary energy source. Megagauss Magnetic Field Generation, i t s A p p l i c a t i o n t o S c i e n c e a n d U l t r aigh - H iPulsed-Power g h P u l s e d - P oTechnology wer Technology For the EMG experiment providing a 1 MA current with 0.5 ps duration of the increase front, in the chamber filled with D-T mixture up to 15 torr pressure, the neutron yield was -1.0*1O1*dpls. We can conclude that using explosive magnetic energy sources produces a factor of 3-4 times higher neutron yield in comparison with capacitive energy sources, while preserving the same current pulse amplitude in the chamber, and rendering the entire system transportable. 4 Study of Instability Growth in High-speed Implosion When the liner is accelerated by a magnetic field [41-481, various phenomena may occur between the liner and the electrode walls. There can occur some advance or lag of the liner boundaries in a pre-wall region of the electrodes, melting or vaporization of the liner material, or a local distortion of the liner shape. In [44,45], the aluminum liner interactions with the electrode walls are described and the choice made by which the liner and electrodes are attached to provide a continuous contact. To make the experiments more informative, a system consisting of two independent liners was used at strictly the same discharge current. To define the liner shape, a radiographic image of the walls-electrodes interaction was made. The helical EMG-100, used as the energy source, had an inner helix turn diameter of 100 mm, length of 700 mm, effective current rise time of 15-17 ps, and it could provide currents of up to 5.8 MA io the liner system (LS). X-rays having pulse duration of -50-70 ns and charging voltage -700 kV recorded the liner motions. A series of explosive experiments was performed and the results are described in detail in [44,45]. 5 Helical EMG as Energy Preamplifier for High-Power Disk EMG A schematic of a disk explosive magnetic generator (2) powered by a helical generator (1) is shown in Fig. 1. Figure 1. 1. Helical explosive magnetic generator (HEMG), 2. Disk explosive magnetic generator (DEMG), 3. Load To power a large, multielement disk generator of 1 m in diameter, a helical generator of 240 mm was developed. [49,50]. When powering a 3-element generator, the following parameters were obtained: Initial inductance of the helical generator 115 pH 85 nH Initial inductance of a 3-element disk generator Initial current of the helical generator powering 28 kA Vlllth INTERNATIONAL CONFERENCE ON MEGAGAUSS MAGNETIC FIELD GENERATION AND RELATED FL,USA, USA, October OCTOBER 18-23,1998 1998 RELATED TOPICS. TOPICS TALLAHASSEE, Tallahassee, FL, 18-23, Final current at the exit of the helical generator Initial energy in a 3-element disk generator of 0 1 m 6 13.7 MA 8MJ Magnetized Plasma Preliminary Heating in MAGO Chamber A device designed to power the plasma chamber is presented in Fig. 2. The helical explosive magnetic generator, II, provides preliminary powering of chamber I using magnetic flux. Upon completion of preliminary powering, a source of rapid powering, III, consisting of the helical explosive magnetic generator, A, and a fast opening switch, B, switches on. Gas discharge takes place in section 1 of the chamber resulting in "sticking" in the magnetic field plasma. Under the effects of the magnetic field, the formed plasma flows out of the first section to the second through nozzle 3. The plasma flow becomes supersonic at the nozzle exit due to the rapid increase in magnetic field. A high-temperature region is formed in the second section, in which deceleration and heating of plasma take place . Figure 2. The schematic of MAGO chamber powered by two HEMGs. Table 1 presents the results of chamber testing in which a 200 mm diameter helical generator with a fast opening switch served as a quick-operating source. A 160 mm diameter helical generator was used as a preliminary powering source. Table 1 7 No. IpnL, 1 2 3 MA 4 3 1.01 I, MA 9.5 10.5 8 ij A/s sTTo"2 3.9-10' 4.0-1012 EEMG. MJ 6.9 10 6.8 N neutrons 1.4-10' J 2.0-1013 4.0-1013 Quick-Operating Superpower Disk EMG High-power, quick-operating sources of energy, able to provide current pulses of tens of megaamperes in the outer load for tens of microseconds (rate of rise is 1012 A/s and higher) are increasingly used in many world laboratories to solve both scientific and engineering problems. Increasingly, in large facilities, the energy delivered to the load during a single experiment is higher and the cost of the parts destroyed in the shot (not only the load, but the facility parts around it, as well) becomes much higher. The protective measures to be taken must be great if the energy delivered to the load is, for example, 100 MJ (equivalent Megagauss Magnetic Field Generation, its Application to Science and Ultra-High Pulsed-Power Technology _____________ ~ ~ ~ to 25 kg of trinitrototluene (TNT)). VNIIEF presently possesses much experience in the development and application of EMGs [ 1,2,22-241. There are advantages in using single-action EMGs at certain energies. Also, there are no stationary systems (e.g. for energy 200 MJ at currents of more than 200 MA) that could provide the output characteristics of EMGs. It is expedient to use helical EMGs for energy levels up to 50 MJ and currents up to 50 MA, while disk EMGs [22-251become preferable for energy levels of 20-30 MJ at currents greater than 30 MA (up to 100 MJ at currents up to 300 MA, see Fig. 3, Table 2). Transition from helical to disk EMGs allows the speed of the current rise in the load to increase by an order of magnitude (up to l O I 3 A/s and higher) without using fast opening switches, although their use is very important in some cases. Among the three types of disk EMGs, the one with disk modules of 400 mm diameter are most widely used. This is due to its modest dimensions, high specific characteristics and comparatively low cost. Several dozens of experiments have been performed with this EMG using between 5 to 25 disks. This EMG was used in the first joint VNIIEFiLANL experiment successfully performed at Sarov in 1993. A l m diameter disk EMG has also been repeatedly and successfully tested. Disks Explosives Insulator I Load - Detonators Figure 3. High-power quick-operating “POTOK’ family disk generator. Table 2. Characteristics of 8 Implosion of 1.5 Kg Condensed Liner with 100 MA Current Pulse One might hope for the creation of a stationary superpower facility in 10 or 20 years capable of accelerating I kg solid liners carrying a 100 MA current pulse, by transmitting 20 MJ or more energy to the liners. However, the technology of quick-operating superpower ‘4111th INTERNATIONAL CONFERENCE ON MEGAGAUSS MAGNETIC FIELD GENERATION AND Tallahassee, FL, 18-23, AND RELATED TOPICS TOPICS. TALLAHASSEE, FL,USA, USA,October OCTOBER 18-23,1998 1998 “POTOK” family helical and disk EMGs, developed at the Electrophysical Department of VNIIEF, accomplished this 10 years ago. The experiments were performed in 1988 . To demonstrate this technology potental, a joint VNIIEFILANL experiment at Sarov, aimed at liner acceleration, was planned two years ago. The initial mass of the accelerated part would be more than 1600 grams, the current pulse no less that 100 MA . Fig. 4 shows the schematic of the device. The current pulse shape from that experiment is shown in Fig. 5. ?20 [--- 1 I00 “d 80 60 t40 9 20 V 0 100 Figure 4. Experimental device schematic. 150 200 250 TIME (psec) 300 Figure 5. Current through the liner pulse shape. Solid, high-velocity liners can be applied to: 1. Generate superhigh pressures of tens of megabars 2. Generate superhigh magnetic fields of 50 MG and more 3 . Magnetize plasma compression until thermonuclear ignition is achieved Magnetic compression of the preliminary heated magnetized plasma is the shortest and the most economical way to achieve ignition 9 MAGO Position Two principle ways to achieve thermonuclear ignition have already become classical: magnetic confinement and inertial confinement. The drawbacks of magnetic confinement are the “cyclopean” dimensions of the facility, high cost and long construction time. The drawbacks of inertial fusion are a very high ratio of the target compression, difficulty in achieving the required compression symmetry and high cost. The drawbacks of magnetic compression (MAGO) are its novelty and singularity. The advantages of MAGO are: 1. Pre-heating and magnetizing the plasma considerably simplify the gas compression ratio requirements (compared to ICF, the requirements are 10 times lower) and ensure necessary symmetry (the requirements become 100 times lower). 2. Bulky and high-cost facilities are unnecessary. Ignition becomes possible with the help of the existing superpowered EMGs. Megagauss Magnetic Field Generation, its Application to Science and Ultra-High Pulsed-Power Technology 3. The cost can be reduced significantly and the ignition occurs much faster. 10 Principle Tenets of MAGO Superhigh magnetic fields formed by explosive magnetic generators are used to: Pre-heat (up to several hundred electron-volts) DT-gas (plasma) provide the required thermal insulation of the fuel confine the charged reaction products within the chamber volume. Subsequent adiabatic compression of the volume occurs with a pre-heated DT-gas by the chamber wall, set in motion by a quick-increasing magnetic field from a superpower EMG having 100-500 MJ of energy storage. The proposed solution of a controlled thermonuclear fusion problem based on thermonuclear target compression by magnetic field, i.e MAGO in Russian, was first presented in 1976 in a very detailed report by Yu. B. Khariton, V. N. Mokhov, V. K. Chernyshev and others at one of the sessions of the USSR Academy of Sciences [181. A short version was published in 1979 in the Reports of the Academy of Sciences (DAN) WI. The MAGO chamber schematic is presented in Fig. 6. Figure 6. MAGO Chamber Schematic vIIthINTERNATIONAL CONFERENCE ON MEGAGAUSS MAGNETIC FIELD GENERATION AND RELATED TOPICS. TALLAHASSEE, FL, USA, OCTOBER 18-23, 1998 Table 3 describes the parameters of the required energy sources and the sequence and conditions of operations. Fable 3 VNIIEF specialists succeeded in photographing a hot zone in self-neutrons (Fig. 7) with a pinhole camera. They have also achieved good repeatability of the results. The following plasma parameters were obtained: Current, generating magnetic field in the chamber Main current pulse with the amplitude of Main current risetime Number of thermonuclear reactions Neutron radiation duration Electron temperature 2 MA 7 MA 1.5-2.0 V S 5 10'3 2 CLS 0.2-0.5 keV Fig. 7 Camera image. Conclusion New types of powerful, fast operating explosive magnetic generators for different thermonuclear and physical applications were invented and then widely successfully used in a large number of experiments. They allowed handling of multi-megampere (up to several hundreds of MA) current sources and made it possible to study many interesting physical phenomena in such fields as high energy density, plasma physics and liner implosions, among others. References 1. 2. 3. 4. 5. Sakharov, A. D., Ludayev, R. Z., Smimov, E. N., et al., Mugnitnuyu kumulafsiu. DAN USSR 196 NO. 1 (1965) pp. 65-68. Sakharov, A. D. Vzryvomagnitnie generatory U.RN.88 No. 4 (1966) p. 725. Sakharov, A. D. Vospominaniya,1 (Prava cheloveka, Moscow, 1996). Terletskii, Ya. P., Poluchenie sverkhsilnykh magnitnykh polei putem bystrogo szhatiya provodiashchikh obolochek. In ZhETF, 32 No.2 (I 957). Fowler, C. H., Gam, W. B., Caird, R. S., Production of very high magnetic fields by implosion. J. Appl. P h y ~31 . 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K., Mokhov, V. N., Protasov, M. S., et al., Investigation of Liner Ponderomotor Units, Used as Drivers on Magnetic Implosion System. In: Proc. VZIIZEEE International Pulsed Power Conference. San Diego, 1991, ed. by R. While and K. Prestiwich (Institute of Electrical and Electronics Engineering, New York, 1991) pp. 438-456. Reinovsky, R. E., Anderson, B. G., Clark, D. A,, et al., HEL-1: a DEMG Based Demonstration of Solid Liner Implosion at 100 MA., I l l h IEEE International Pulsed Power Conference, Baltimore, Maryland, 1997. Chernyshev, V. K., Protasov, M. S., Shevtsov, V. A., Penye diskovye vzrivomagnitnye generatory. Protasov, M. S.,Arkhipov, B. V., Petrukhin,A. A., Prokopov, V. A., Chernyshev, V.K., Shvetsov, V. A., Bystrokhodnyi diskovyi vzryvomagnitnyi generator. Sverkhsylnye magnitnye polya., Fizika. Tekhnika. Primenenie. Trudy 3 Mezhdunarodnoi konferentsii. Moscow, Nauka (1983) p. 23,26. Chernyshev V. K., Mohov, V. N., On the progress in the creation ofpowerful explosive magnetic energy Sources for thermonuclear target implosion. Proceedings of 8IhPulsed Power Conz, San Diego (1991) p. 395. vIIthINTERNATIONAL CONFERENCE ONON MEGAGAUSS MAGNETIC GENERATION Vlllth INTERNATIONAL CONFERENCE MEGAGAUSS MAGNETICFIELD FIELD GENERATION TOPICS. TALLAHASSEE, FL,USA, USA,October OCTOBER 18-23,1998 1998 AND RELATED TOPICS Tallahassee, FL, 18-23, 23. 24. 25. 26. 27. 28. 29. 30. 3 1. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. Chemyshev, V. K., Protasov, M. S., Shvetsov, V. A,, et al., Explosive magnetic generators of "Potok" family. Proceedings of 8IhPulsedPower Conz, San Diego (1991) p. 419. Chernyshev, V. K., Grinevich, B. E., Vakhrushev, V.V., Mamyshev, V. I., Scaling Image of 90 MJ Explosive Magnetic Generators. In Proceedings of Fifth International Conference on Megagauss Magnetic Field Generation and Related Topics, p. 347. Chemyshev, V. K., Demidov, V. A,, Kazakov, S. A., et al., Multielement Disk EMG powering, Using High-Inductive Helical Generators. In: Megagauss Magnetic Generation and Pulsed Power Applications, Ed. by M. Cowan and R. B. Spielman. (Part I., Nova Science Publishers, Inc., N.Y., 1994) pp. 519-524. Mokhov, V. N., Chemyshev, V. K., Yakubov, V. B., et al., 0 vozmozhnosti resheniya problemy upravlyaemogo termoyademogo sinteza na osnove magnitogazodynamicheskoi kumulatsii energii. DAN USSR, 247 No. 1, (1979). Buyko, A. M., Volkov, G. I., Garanin, S. F. el al., Issledovanie vozmozhnosti polucheniya termoyademoi zamagnichennoi plasmy v sisteme s magnitnym obzhatiem - MAGO. 3 Zababakhinskie nauchnye chteniya, January 1992 , Kyshtym, Russia. A.Buyko,, G.Volkov,, S.Garanin,, et al., Investigation of Possibility of Thermonuclear Magnetized Plasma in the System with Magnetic Implosion-MAGO. Proceedings of the 9'h International Pulsed P ower Conference, Albuquerque (1993). Shearer, J. W., Abraham, F. F., Alpin, C. M., el al., Explosive-Driven Magnetic Field Compression Generators. Journal OfAppliedPhysics, 39 No. 4 (1968) pp. 2102-2116. Filippov, N. V., Obzor eksperimental'nykh rabot vypolnennykh v IAE im. Kurchatova I.V., PO issledovaniyu plasmennogo focusa. Fizikaplasmy, 9 No. 1 (1983) pp. 25-44. Ware, K. D., Williams, A. H., Clark, R. W., Operation of a 720 kJ, 60 kV, Dense Plasma Focus. Bull. Amer. Phys. SOC.,18 No. 10 (1973) p. 1363. Haines, M. G., Dense Plasma in Z-pinches and the Plasma Focus. Phil. Trans. Roy. SOC.Lond. A300 (1981) pp. 649-663. Gribkov, V. A,, Filippov, N. V., Istoriya razvitiya i poslednie dostizheniya v issledovaniyakh PO plsmennomu focusu. Preprint FIANNo. 94, Moscow (1979) p. 49. Getes, D. C., Demeter, L. I., Production of 14 MeV Neutrons with a 500 kJ Coaxial Plasma Gun. Bull. Amer. Phys. SOC.15 No. 11 (1970) p. 1464. Bernard, J., Boussinesq, J., Morin, J. et al., An Explosive Generator - powered plasma focus, Phys. Lett. 35 A No.4 (1971) pp. 288-289. Chemyshev, V. K., Tsukerman, V. A., Gerasimov, V M., et al., Vliyanie zameny kondensatomogo istochnika energii induktivnym na parametry plasmennogo focusa. ZhTF 56 No. 5 (1986). Freeman, B. L., Caird, R. S., Erickson, D. J. et al., Plasma Focus Experiments Powered by Explosive Generators. LA-UR-83.1083. Caird, R. S., Erickson, D. J., Freeman, B. L. et al., Neutron Yields from an Explosive Generator Powered Plasma Focus. IEEE Int. Con$ on Plasma Science, (Madison, 1980. Conf. Rec.) pp. 40-41. Freeman, B. L., Caird, R. S., Erickson, D. J. et al., Plasma Focus Experiments Powered by Explosive Generators. Third Int. Con$ on Megagauss Magnetic Field Generation and Related Topics. BookofAbsfracts. Novosibirsk, (1983) p. 17. Azarkh, Z. M., Makeyev, N. G., Tsukerman, V. A. et al., Primenenie kamer s plasmennym focusom dlya rentgenostruktumykh issledovanii polikristallicheskykh obraztsov s nanosecundnymy ekspozitsiyami. DAN USSR 232 No. 5 (1977) pp. 1049-1051. Pavlovskii, A. I., Ultrahigh Magnetic Fields Cumulation. Megagauss Fields and Pulsed Power Systems. MG- V, ed. by V. M. Titov and G.A. Shvetsov (Nova Science Publishers, New York) pp. 1-13. Degnan, J. H., Baker, W. L., Beason, J. D., et al., Multi-Megajoule Shaped Solid Liner Implosions. Ibid, pp. 623-630. Megagauss Magnetic Field Generation, its Application to Science and Ultra-High Pulsed-Power Technology 43. Degnan, J. H., Alme, M. L., Baker, W. L., Buff, J. S. et al., Megagauss Technology and Pulsed PowerApplications. MG-iV, ed. by C. M. Fowler, R. S. Caird and D. J. Erickson. (Plenum Press. New York and London, 1987) pp. 699-706. 44. Chernyshev, V. K., Zharinov, Ye. I., Kudelkin, I. D., et al., Cylindrical Liner: Implosion Dynamics Under EMG Magnetic Pressure. Book of abstracts. MG-Vi, Albuquerque, New Mexico (1992) p. 92. 45. Chernyshev, V. K., Zharinov, Ye. I., Mokhov, V. N., et al., Study of Imploding Liner-Electrode Wall Interaction. BEAMS ’96. Proceedings 1, I”‘ International Conference of High Power PurticleBeams (Prague. Czech Republic June 10-11, 1996) p. 558. 46. Bujko, A. M., Garanin, S. F., Demidov, V. A,, et al., Investigation of the Dynamic of a Cylindrical Exploding Liner Accelerated by a Magnetic Field in the Megagauss Range. Megagauss Fields and Pulsed Power Systems, Ed. by V. M. Titov and G. A. Shvetsov. MG-V, (Nova Science Publishers) p, 743. 47. Megagauss and Megaainpere Pulse Technology and Applications. Ed. by V. K. Chemyshev, V. D. Selemir, L. N. Plyashkevich. Proceedings of 7IhInternational Conference on Megagauss Magnetic Field Generation and Related Topics, (Sarov, VNIIEF, 1997). 48. Chemyshev, V. K., Zharinov, E. I., Grinevich, B. E., et al., Uskorenie ploskikh metallicheskikh i dielektricheskikh lainerov magnitnym polem. Zababakhinskie nauchnye chteniya, 14-17 January 1992 (tezisy dokladov), Kyshtym, Dal’nya Dacha. 49. Chernyshev, V. K., Volkov, G. I., Ivanov, et al., Explosive Magnetic Source, Storing 30 MJ of Energy to Power Gaseous Ponderomotor Unit. In Proceedings of the 6Ihinternational Conference on Megagauss Magnetic Field Generation and Pulsed Power Applications, p. 551. 50. Chernyshev, V. K., Grinevich, B. E., Vakhrushev, V. V., Mamyshev, V. I., Scaling Image of 90 MJ Explosive Magnetic Generators. In Proceedings of the Fifth International Conference on Megagauss Magnetic Field Generation and Related Topics, p. 347. Vlllth INTERNATIONAL CONFERENCE ON MEGAGAUSS MAGNETIC FIELD GENERATION AND RELATED RELATEDTOPICS TOPICS. TALLAHASSEE, FL,USA, USA,October OCTOBER 18-23,1998 1998 Tallahassee, FL, 18-23, AND THE DIRAC EXPERIMENTS - RESULTS AND CHALLENGES R. G. CLARK, J. L. O’BRIEN, A. S. DZURAK, B. E. KANE, N. E. LUMPKIN, D. J. REILLEY, R. P. STARRETT National Pulsed Magnet Laboratory and Semiconductor Nanofabrication Facility, University of New South Wales, Sydney, Australia D. G. RICKEL, J. D. GOETTEE, L. J. CAMPBELL, C. M. FOWLER, C. MIELKE, N. HARRISON, W. D. ZERWEKH, D. CLARK, B. D. BARTRAM, J. C. KING, D. PARKIN Los Alamos National Laborato y, New Mexico, USA H. NAKAGAWA, N. MIURA Institute for Solid State Physics, University of Tokyo, Japan The 1997 international Dirac I1 Series held at Los Alamos National Laboratory involved low temperature electrical transport and optical experiments in magnetic fields exceeding 800 T, produced by explosive flux compression using Russian MC-1 generators. An overview of the scientific and technical advances achieved in this Series is given, together with a strategy for future work in this challenging experimental environment. A significant outcome was achieved in transport studies of microfabricated thin-film YBCO structures with the magnetic field in the CuO plane. Using a GHz transmission line technique at an ambient temperature of 1.6 K, an onset of dissipation was observed at 150 T (a new upper bound for supcrconductivity in any matcrial), with a saturation of resistivity at 240 T. Comparison with the Pauli limit expected at B = 155 T in this material suggests that the critical field in this geomehy is limited by spin paramagnetism. In preparation for a Dirac 111 series, a systematic temperature-dependent transport study of YBCO using in-plane magnetic fields of 150 T generated by single-turn coils, at temperatures over the range 10-100 K, has been undertaken in collaboration with the Japanese Megagauss Laboratory. The objective is to map out the phase diagram for this geometry, which is expected to be significantly different than the Werthamer-Helfand-Hohenberg model due to the presence of paramagnetic limiting. Nanofabricated magnetometers have also been developed in a UNSW-LANL collaboration for use in Dirac 111 for Fermi surface measurements ofYBCO in megagauss fields, which are described. 1 Introduction The Dirac Series of experiments was instituted in 1996 at Los Alamos National Laboratory so that a variety of experimental projects could access fields approaching 1000 T to study new physical phenomena in condensed matter systems. The second Series was undertaken in 1997 and a third Series is planned for 1999, with the overall program including groups from six nations. Central to this has been a US-Russia collaboration in which Russiandeveloped MCl-class [ 11 flux-compression generators have been provided for the experiments. The Series has included studies of magneto-optics in magnetic materials  and semiconductors , quantum limit effects in organic metals  and chemical bond strengths in organic materials [ 5 ] . Megagauss Magnetic Field Generation, its Application to Science and Ultra-High Pulsed-Power Technology ANCHO CANYON PBX - 9301 EWiDSNE I Wlow Cyiindtr 1 I I YE I & BUNKER opm. lbnr RUIM7A I i I ' , 1 A F W I MXIW RLD OAlA U- t a n , IS% IU TRAILER Figure 1. Configuration for implosive flux compression experiments at Los Alamos National Laboratory, USA. The thick lines at top-left represent low-loss cables for the GHz transport measurements. One of the most ambitious experiments within the Dirac Series has been the attempt to obtain reliable transport data on both semiconductor and high-? superconductor materials by an Australia-Japan-USteam. The experiments required a number of innovations for the elimination of Faraday pick-up . Measurements during Dirac I [6,7] on semiconductor heterostructures demonstrated the success of the technique, paving the way for a fruitful and detailed investigation of the high-? superconductor, YBa,Cu,O,, (YBCO) during Dirac 11. Here we discuss the measurements on YBCO in detail, which have provided the first evidence of paramagnetic limiting in the high-T cuprates [8,9], as well as previewing planned experiments for Dirac I11 in 1999. 2 Experimental Innovations for ps Transport Measurements The conditions during an MC1 generator pulse are extreme, with the generator, cryostat and samples all destroyed after the pulse. Fig. 1 shows the experimental arrangement for the low temperature measurements. During the pulse, dB/dt can reach lo9T/s, creating voltage up to1 kV in a conducting loop of area 1 mm2. Minimization of Faraday pick-up was vIIthINTERNATIONAL CONFERENCE ON MEGAGAUSS MAGNETIC FIELD GENERATION AND RELATED TOPICS. TALLAHASSEE, FL, USA, OCTOBER 18-23, 1998 ~ therefore critical and specially designed  coplanar transmission lines (CTLs) patterned on a printed circuit board (PCB) substrate were used to achieve this. Eddy current heating of the CTL connections represented a potential problem, since Cu of thickness 9 ym can heat above 10 K during the field pulse .Thermal isolation of the samples was achieved by patterning thin (80 nm) Au CTLs directly onto the samples, bridging a 2 mm gap in the thick CTLs on the PCB (see Fig. 2). To avoid the problem of erratic ohmic contacts at large B, a layer of Si,N, dielectric was sandwiched between the YBCO and the metal CTLs [lo], to achieve a capacitive coupling to the sample. t - I f PCB Figure 2. Flip-chip sample mounting. Thin Au transmission lines (80 nm) bridge gaps in the thicker lines on the PCB. Six Au pads (300 nm) provided contacts and the chips were held in place using a heat curable epoxy. Here a = 150 ym, b = 10 ym, t = 9 ym and w = 410 pm. 3 Transport Measurements of YBCO to 300 T We first discuss results obtained during the Dirac-I1 Series in 1997, which suggest that critical fields in YBCO for Blc-axis are determined by paramagnetic limiting. The experimental configuration shown in Fig. 2 probes the in-plane resistivity pab of YBCO through its modulation of the transmission S of GHz radiation. If the sample is superconducting, the inner and outer conductors of the CTL triplet are shorted so that S is zero, except for a small contribution from cross-talk, whereas a perfect insulator has no effect on transmission. Although the sample impedance at 1 GHz is a complex quantity the measurement provides no phase information, so for simplicity, we assume that the impedance corresponds to a scalar resistivity p. Figure 3 shows results for T = 1.6 K, i.e. TI? - 0.02, in an 850 T MC1 field pulse. Only data to 320 T are plotted, since results above this field were obscured by noise, discussed below. Megagauss Magnetic Field Generation, its Application to Science and Ultra-High Pulsed-Power Technology 0 100 2 00 300 Magnetic Fteld, B (7) Figure 3. Measured normalised transmission S data for YBCO with B l c obtained in an MCl pulse with T = 1.6 K, v = 0.9 GHz and a power -1 mW at the sample. The bold line is a fit to this S data. A small averaged noise background (fine line) has been subtracted from the data. The upper curve is the calculated resistivity, assuming the transmission function S(pOb)shown in the inset. The dip in Sat p - 5 ~ 1 0Bm . ~ is well understood and results from interference between ingoing and reflected signals on the CTLs. Taken from Ref. . ( 0 ) We observe the onset of a dissipative (p > 0) state at B0;* = (150 f 20) T and define B e g b= (240 2 30) T as the field at which S, and therefore p. saturates, using an asterix to indicate that the transition may result from paramagnetic limiting. The uncertainties in B reflect the noise-limited accuracy with which we can define inflection points in the S data, together with an estimate of timing accuracy. To our knowledge Bonab- 150 T is the largest field in which a superconducting phase has been observed. A broader superconductor-normal(S-N) transition than observed here, spanning 75 T - 340 T, has been observed in previous measurements [ 11,121,possibly due to the high frequency (94 GHz) used. We also note that the strongest saturation feature present in this data [ 11,121 is near our critical field of 240 T. Vlllth INTERNATIONAL CONFERENCE ON MEGAGAUSS MAGNETIC FIELD GENERATION AND RELATED TOPICS Tallahassee, FL, USA, October 18-23, 1998 To determine the response in Fig. 3 accurately it was necessary to subtract from the raw data a noise background (as shown). Below 300 T the noise is small and occurred in the interval 150 T - 180 T , due to the fusion of metal wires comprising the second of the three generator liners. Above 300 T wire fusion proceeded in the third liner with the noise creating severe problems for transport measurements. To avoid this problem during Dirac I11 in 1999, one or two of the inner liners will be removed from the MC-1 generators. Thus configured, the generators are still capable of reaching 400 T, which exceeds the critical field in these samples and offers the opportunity of observing any possible reentrant states above B*c2ab. Figure 4. GHz transport data on YBCO obtained in destructive single-turn coil pulses to 150 T. (Top) Raw transmission S data at T = 60 K and 70 K. The inset shows the experimental arrangement and the field profile B(t). Data is shown for times after the arrow marked a in the inset. (Bottom) Magnetorcsponse S(B) at T = 80 K, 77 K, 70 K, 66 K, 65 K and 60 K, in order of increasing Born.The curves are fits to the data, with the raw data at 80 K shown for comparison. Also shown are the definitions used for B, and the onset field, Bo,,. Megagauss Magnetic Field Generation, its Application to Science and Ultra-High Pulsed-Power Technology 4 Single Turn Coil Measurements of YBCO to 150 T For Dirac I1 and the coming Dirac I11 Series, complementary measurements have been made at the Japanese Megagauss Laboratory using single-turn coil pulsed field systems [ 131 to collect systematic data sets and study dynamic effects through an examination of any hysteresis present. For bore sizes -10 mm these systems produce -30 T non-destructively, or -150 T in pulses which destroy the generator but leave the sample unperturbed. The rise time is -3 p s (see inset to Fig. 4, Top), giving a peak dB/dt -lo8 T/s which, while around an order of magnitude smaller than the MCl generators, provides indicative information about dynamic effects. Results obtained prior to Dirac I1 using non-destructive pulses to 30 T showed that dynamic effects on a ps timescale are negligible in YBCO with B l c . This conclusion has been reinforced in recent measurements using destructive shots to 150 T . Fig. 4 shows GHz transmission S data obtained at a variety of temperatures below T,. For these measurements it was possible to tune the frequency so that S = 0 when the film was superconducting. Transmission increased monotonically with p as B drove the sample into the normal state. The raw data in Fig. 4 show a number of positive-going perturbations to S corresponding to GHz noise, probably associated with RF emissions from the vaporizing coil. The underlying sample response S(B) is clear, however, and has been fitted for a series of temperatures in Fig. 4(BOttOm). As the inset to Fig. 4(Top) shows, the coil generates a damped oscillating B that produces a number of cycles before destruction. The raw data in Fig. 4(Top) show S over this h l l period except for the first 2 ps, where large electrical noise obscures the data. Note that there is no measurable hysteresis in S between B increasing and decreasing throughout the resistive transition. This is significant, since it implies that the S-N transition is a quasi-equilibrium process, even in p s pulses to 150 T. Dynamic effects associated with flux motion or heating caused by the large dB/dt are clearly not as important as one might suspect, providing confidence in interpretation of the data from Dirac flux-compression measurements. The critical fields B, and resistive onsets Boris as defined in Fig. 4(BOttOm) are plotted for a detailed data set on a single YBCO sample to create a B-Tphase diagram (Fig. 5). B, varies linearly with T u p to -100 T, with a slope close to the often quoted value dBJdT = - 10.5 T/K obtained by Welp et al.  from magnetization measurements in magnetic fields up to 6 T. 5 Discussion and Strategy for Dirac I11 It is clear from our data that the low-TS-Ntransition for YBCO is very different for the two orientations B l c and B//c. The phase diagram for B//c (inset to Fig. 5a), from Ref. [ 161, is in good agreement with the BCS model of Werthamer-Helfand-Hohenberg (WHH) which, neglecting contributions from the Zeeman energy of the electron spins, gives B0,2(T= 0) = 0.70 T,(dBc~/dT)I~, . Inserting the slope a = -2.0 T/K gives Boc,(T= 0) = 120 T which . Vlllth INTERNATIONAL CONFERENCE ON MEGAGAUSS MAGNETIC FIELD GENERATION AND RELATED TOPICS Tallahassee, FL, USA, October 18-23, 1998 55 60 65 70 75 80 85 T (I0 Figure 5 . (a) YBCO phase diagram for B l c determined from GHz measurements using single-turn coils. The symbols marked (A) represent B, (BonJ values as defined in Fig. 4(b). The dashed line corresponds to dBJdT = - 10.5 T K , determined from magnetisation measurements by Welp et al. [I 51. Inset: Phase diagram for Bllc determined from transport measurements using single-turn coils [taken from Ref. 161. (b) Full YBCO phase diagram for B l c . The symbols (A)represent B, (Bon3)values obtained from MC1 and single-turn coil data in Figs. 3 and 4. The solid line represents B, calculated for a d superconductor while the dashed line depicts a first order transition from a BCS state 2-2 to a Fulde-Ferrell state [taken from Ref. 201. The dotted function is the WHH prediction assuming no spin paramagnetism. The vertical lines show planned temperatures for MC-1 shots during Dirac 111. Megagauss Magnetic Field Generation, its Application to Science and Ultra-High Pulsed-Power Technology is consistent with that observed experimentally. Using the same model for B l c , however, predicts B',(T = 0) = 625 T which is almost a factor of three greater than the measured value (see Fig. 5b). One explanation is that a misalignment of B could probe properties in the a-b planes, which would reduce the observed Bc,. This effect can be dramatic for highly anisotropic materials such as organic superconductors [ 181 but should be small for YBCO that has much smaller anisotropy. A more probable explanation is that for B l c the Zeeman energy associated with maintaining the singlet state exceeds the superconductor energy gap well before Boc,is reached. The field B, at which this occurs is referred to as the paramagnetic (or Clogston) limit which, from BCS theory, is given by B, = y? with y = 1.84 T/K . For our samples we have B,- 155 T, which is above B L for Bllc but well below it for B l c . Our data may therefore represent the first observation of paramagnetic limiting for a cuprate superconductor, providing additional experimental information relevant to current models of high-? superconductivity.Recent interpretations in terms of a d2-2 state have motivated a number of new models. The phase diagram predicted by one model , which considers the coupling of B only to the spins of the electrons, is plotted in Fig. 5(b). The agreement with our low-T data is remarkably good. In this model a first order phase transition (dashed line) occurs for TI?< 0.5 between a zero momentum pairing state at low B and a finite momentum, or Fulde-Ferrel (FF), state at higher B. We note that our low-T Bon5coincides with this transition, although p would be expected to remain at zero throughout the FF phase. Our data provide a usehl preliminary picture of the YBCO phase diagram with strong paramagnetic effects and the primary aim for Dirac 111 is to complete this diagram, with shots at several temperatures as shown in Fig. 5(b). 6 Development of de Haas-van Alphen Coils for Dirac I11 For the 1999 Dirac 111 series it is also planned to extend a previous measurement of the de Haas-van Alphen (dHvA) effect and Fermi surface of YBCO in a 100 T flux compression system  to higher magnetic fields. To achieve this aim, it is necessary to develop sensitive, perfectly compensated dHvA coils using electron beam lithography, for use with small samples, which can be connected to the coplanar transmission line geometry that minimizes dB/dt pickup in the MC-1 generator environment. Figure 6. dHvA coil magnetometers used in pulsed fields and fabricated at UNSW. a) Optical micrograph showing full device with bond wires attached. The outermost coil is 450 pm on a side. (b) SEM image showing the individual windings of the coil, fabricated by electron-beam lithography.This coil has 250 nm metal wires with 250 nm spacing. Vlllth INTERNATIONAL CONFERENCE ON MEGAGAUSS MAGNETIC FIELD GENERATION AND RELATEDTOPICS Tallahassee, FL, USA, October 18-23, 1998 , $it , ,L *' j";, As a first step in this direction, dHvA coils of this design have been fabricated for tests in ms pulsed fields (see Fig. 6). The coil geometry and data taken for a LaB, single crystal test sample in a 50 T pulse at 4 K are shown in Fig. 7. For the orientation of this crystal, the three branches of the a frequency (al,az,aJ [22,23] are clearly observed at 4 K (together with the second harmonic 2 a J on a small sample with a coil comprised of only 46 inner and 16 outer windings of 0.5 pm width and 1.5 pm spacing, using a preamplifier gain of only 5000. 5000 loow 15000 Frequency (T) 20~0 Figure7. Fourier transform of the dHvA signal measured in LaB, at 4 K on the falling magnetic field, analyzed over the range 30-50 T in a ms pulse. The single crystal sample with linear dimensions -200 pm was orientated with the [OOl] axis at an angle of -15" to the pulsed field (towards [loll). The inset shows the nanofabricated dHvA coil geometry. Compensated coils with both 0.5 pm and 0.25 pm wide gold lines on a GaAs substrate have been developed, comprised of46 (181) inner turns and 16 (60) countenvound outer turns, respectively. The coils are designed for connection to coplanar transmission lines developed for the Dirac Series transport measurements. A number of technical difficulties remain to be solved for the more stringent environment of the MC-1 shots, associated with details of the connection of the magnetometer coil to the CTLs and screening of the CTLs for dHvA measurements. The ms pulsed field test results are nevertheless encouraging and highlight the importance of nanofabrication technology to advances in megagauss magnetic field measurements. 7 Conclusions The Dirac Series has motivated significant innovations for electrical transport measurements in megagauss magnetic fields, allowing a detailed study of the phase diagram of YBa,Cu,O,-,. Our data suggests that with B directed along the CuO planes, paramagnetic limiting determines the upper critical field, the first evidence of this effect in an optimally doped high-T, material. Additional developments in nanofabricated dHvA coils provide an opportunity to study the Fermi surface of this important cuprate superconductorabove 100 T. Megagauss Magnetic Field Generation, its Application to Science and Ultra-High Pulsed-Power Technology ~~ References 1. Pavlovskii, A.I., et al., in Megagauss Physics and Technology, Ed by P.J. Turchi, Plenum, New York, (1980) p. 627. 2. O.M. Tatsenko, et al., Physica B 246-247, (1998) p. 315; and these proceedings. 3. Brooks, J. S., et al., Physica B 246-247, p. 50 (1998); and these proceedings. 4. Brooks, J. S., et al., Los Alamos Preprint Report LA-UR 96-3472; J. S. Brooks, J. S. et al., Proc. Megagauss VIL Sarov - Russia, (1996). 5. Maverick, A. S., Butler, L. G., Int. J. Quant. Chem. 64, (1997) p. 607. 6 . Kane, B. E., et al., Rev. Sci. Instu. 68, (1997) p. 3843. 7. Kane, B.E., et al., Proc. Megagauss VIZ, Sarov - Russia, 1996. 8. Dzurak, A. S. et al., Phys. Rev. B 57, R14084 (1998). 9. Dzurak, A. S., et al., Physica B 246-247, (1998) p. 40. 10. For fabrication details see: Lumpkin, N. E., et al., Physica B 246-247, (1998) p. 395. 11. Goettee, J. D., et al., Physica C 235-240, (1994) p. 2090. 12. Bykov, A. I., et al., Physica B 211, (1995) p. 248. 13. Nakao, K., et al.,J. Phys. E 18, (1985) p. 1018. 14. O’Brien, J. L. et al., to be published. 15. Welp, U., et al., Phys. Rev. Lett. 62, (1989) p. 1908. 16. Nakagawa, H., et al., Physica B 246-247, (1998) p. 429. 17. Werthamer, N. R., Helfand, E., Hohenberg, P. C. Phys. Rev. 147, (1966) p. 295. 18. Wanka, S., et al., Phys. Rev. B 53, (1996) p. 9301. 19. Clogston, A. M., Phys. Rev. Lett. 9, (1962) p. 266. 20. KunYang and Sondhi, S. L., cond-mat!9706148 2 (1998). 21. Fowler, C. M., et al., Phys. Rev. Lett. 68, (1992) p. 534; and Comment by Springford, M., Meeson, P., Probst, P-A,, Phys. Rev. Lett. 69, (1992) p. 2453. 22. Ishizawa, Y., et al., J. Phys. SOC.Jap. 42, (1 997) p. 112. 23. Harrison, N., et al., Phys. Rev. Left. 80, (1998) p. 4498. Vlllth INTERNATIONAL CONFERENCE ON MEGAGAUSS MAGNETIC FIELD GENERATION AND RELATED TOPICS Tallahassee, FL, USA, October 18-23, 1998 EXPLOSIVE FLUX COMPRESSION: 50 YEARS OF LOS ALAMOS ACTIVITIES C. FOWLER, D. THOMSON, W. GARN Los Alamos National Laboratov, Los Alamos, NM, USA Los Alamos flux compression activities are surveyed, mainly through references in view of space limitations. However, two plasma physics programs done with Sandia National Laboratory are discussed in more detail. 1 Introduction In this section, we briefly outline major Los Alamos (LANL) flux compression activities. More detailed discussions are given of two programs done with Sandia National Laboratories, (SNL) intermittently from 1966 to 1973. Use of flux compression generators (FCGs) to power 8-pinches is discussed below. The “Birdseed” program, in which 150200 kJ of neon plasma was injected into the ionosphere, is discussed later in this paper, together with plans for a more energetic system. The first open description of the Los Alamos objectives was published in [l], which featured the use of high magnetic fields made at Los Alamos to compress D-T plasmas to make large neutron bursts, for solid-state investigations, and to accelerate matter. These are all topics that remain relevant today. Later, unclassified Los Alamos activities were surveyed at the first Megagauss Conference (1965), . The next Megagauss Conference took place in 1979 . Other activities between these conferences included high field solid-state and isentropic compression experiments. Component development included construction of megavolt transformers and FCG improvements, as with the plate generator. FCG uses as power supplies for railguns, the plasma focus, laser generation, e-beam machines and soft X-ray generators are described in later Megagauss Conference Proceedings, as is the development of high current opening switches.A collaborative flux compression program with Los Alamos and Russian scientists from Arzamas- 16 began in 1993,and included Magnetized Target Fusion and high field experiments , also reported at MG VII. Little of our solid-state work has appeared in the Megagauss Proceedings. However, surveys appear in [5,6,7]. More recent work has been done in the “Dirac” shot series where scientists from the USA and several other countries have collaborated on high field experiments using Russian MC-1 high field generators and Los Alamos strip generators. Various aspects of this program are treated at this conference and at the preceding MG VII Conference. 2 Explosive-Driven @-Pinch Experiments 2.1 @-PinchLiner Implosion Experiments Early experiments [2a,c, 81 at Los Alamos to apply explosively driven flux compression (MG fields) to high temperature plasmas were exploratory, and involved creating a fast theta pinch inside a thin, implodable cylindrical 8-coil. Parameters were chosen to achieve MG fields with systems then available at Los Alamos, and used early 8-pinch data (Scylla I, Scylla 111) [9,10]. Implosion of the plasmdmagnetic system was started using high T high @ plasma confined by the axial magnetic field. Megagauss Magnetic Field Generation, its Application to Science and Ultra-High Pulsed-Power Technology In these experiments, a good diagnostic neutron signal verified that the initial plasma was in place as expected, and gave a measure of the plasma behavior vs time during the explosive driven phase. Fundamental problems existed. Plasma confinement in the short coil (-25 cm) @pinches available for the firing point was limited to 2-3 psec due to endloss, flute instabilities [8,10,11] and to field asymmetries [2c]. In 1966, a new &pinch (Scyllacita) with a faster capacitor bank was used to create the initial plasma . A new side-fed coil implosion system eliminated field asymmetries. Since the basic plasma confinement time limitation with the short 0-coil (-3 ps) remained, as did the quenching effect of the imploding discharge tube, we did not pursue this approach beyond one Scyllacita shot at the firing site. However, the goal of achieving fusion with MG fields in imploding liners remains valid today. We suggest developing a technique, such as an FRC [ 121, to inject an initial, high-beta plasma axially into a clean, resistive liner implosion system at the proper time [2c] for explosive compression to 4 MG or greater. For good confinement, the implosion system length should be increased to one half meter or more. Parameter studies of FRC transport and injection characteristics at high densities (>lOI7/ cm’) would be needed to fully explore the feasibility of this approach, since only plasmas of substantially lower densities have been so transported to date. 2.2 The Explosive Generator Powered @Pinch In 1967, Los Alamos and Sandia Laboratories collaborated in a series of generator powered 0-pinch experiments using Sandia generators [ 13-16]. Two sizes of helical generators were used: the Model 106 generator (5# of PBX 9404 explosive) and the larger Model 169 (17# of PBX 9404 explosive). Exploding wire fuses were used to sharpen the pulses to drive the &pinch coils. The 0-coils were switched in when the voltage across the fuses reached preselected voltages. The initial plasma was created by first putting a few kG bias field Bz in the coil, then passing a linear z-current through the deuterium to preionize it, and finally applying the main drive field to heat and compress the plasma. Nine shots were fired, five with the Model 106 generator and four with the Model 169. Table 1 of [ 161 lists conditions for each shot. The pre-ionized plasma was created inside a 2 mm wall Pyrex or quartz discharge tube with a 40 kA linear current discharge (from a 7.5 pF, 15 kV bank), which was shorted out after a half-cycle to eliminate axial current before switching in the generator. Discharge tube conditioning for each shot involved warm-up 8-pinch shots with an auxiliary capacitor bank [ 14-16]. The generator-powered 0-pinch shot was then fired, complete with preionization, bias field and diagnostics, within 30-60 minutes of the last warm-up shot. Results of the nine generator driven pinch shots are also given in Table I [ 161. Time resolved neutron yields, measuring plasma behavior, have been reported [14171. The shot series demonstrated the importance of reverse bias field, tube conditioning, preionization, and particularly the initial voltage, V,, applied to the preionized plasma. Good diagnostic neutron yields were obtained on 7 of the 9 shots. Results for shots 8 and 9 are shown in Fig. 1, which gives the time history of the applied magnetic field (Bz) and the resulting neutron yield rate for each shot. The highest neutron yield (1.4x108)occurred when all drive parameters were optimized. The maximum neutron yield rate per unit coil Vlllth INTERNATIONAL CONFERENCE ON MEGAGAUSS MAGNETIC FIELD GENERATION AND RELATED TOPICS Tallahassee, FL, USA, October 18-23, 1998 ~ length was comparable to or better than those for laboratory theta pinches worldwide [181. In 1968, the Frascati group conducted five generator-driven8-pinch shots with at least one neutron yield (