Cosmical Magnetism NATO ASI Series Advanced Science Institutes Series

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Series C: Mathematical and Physical Sciences - Vol. 422 Cosmical Magnetism

edited by D. Lynden-Bell Institute of Astronomy & Clare College, , U.K.

Springer Science+Business Media, B.V. Proceedings of the NATO Advanced Research Workshop on Cosmlcal Magnetlsm Cambridge, U.K. July 5-9, 1993

A C.I.P. Catalogue record for this book Is available from the Ubrary of Congress.

ISBN 978-94-010-4485-1 ISBN 978-94-011-1110-2 (eBook) DOI 10.1007/978-94-011-1110-2

Printed on acid-tree paper

AII Rights Reserved @ 1994 Springer Science+Business Media Oordrecht Originally published by Kluwer Academic Publishers in 1994 Softcover reprint of the hardcover 1st edition 1994 No part of the material protected by this copyright notice may be reproduced or utilized in any form or by any means, electronic or mechanical, including photo• copying, recording or by any information storage and retrieval system, without written permission from the copyright owner. TABLE OF CONTENTS

Preface VII

Index to Photograph Vlll

Conference Photograph IX

Professor Leon Mestel's Photograph X

List of Participants xi

THE EARTH'S DYNAMO H.K. Moffatt

SOLAR CORONAL HEATING BY MAGNETIC FLUX INTERACTION 11 E.R. Priest, C.E. Parnell and G.J. Rickard

MAGNETIC ENERGY DISSIPATION AND CORONAL HEATING BY DC CURRENTS 25 J. Heyvaerts

MAGNETIC WINDS FROM STARS AND DISKS 33 H.C. Spruit

MHD WINDS AND JETS 45 K. Tsinganos and C. Sauty

MAGNETIC WHITE DWARFS 55 J.D. Landstreet

AP-STARS: A NEW LOOK AT HOLDING AND CONFINING THEIR MAGNETIC FIELDS 67 F. Meyer

MAGNETIC FIELDS AND STAR FORMATION 73 E.G. Zweibel

SPIN-UP AND SPIN-DOWN INDUCED MAGNETIC FIELD CHANGES IN NEUTRON STARS 87 M. Ruderman

GAMMA-RAYS FROM MAGNETOSPHERES: PHYSICS OF THE PROCESS AND EFFECTS ON PARTICLE TRAJECTORIES 99 F.D. Kahn and A.A. da Costa

COSMIC-RAY PRODUCTION OF LIGHT ELEMENTS IN THE EARLY GALAXY 113 B.E.J. Pagel vi

REPLACEMENT CONCEPTS FOR TURBULENT DIFFUSION OF MAGNETIC FIELDS IN STARS AND GALAXIES 123 E.N. Parker

THE MAGNETIC FIELD IN THE LOCAL SPIRAL ARMS 131 R.D. Davies

OBSERVATIONS OF MAGNETIC FIELDS IN (NEARBY) GALAXIES 143 R. Wielebinski

ORIGIN OF THE SEED MAGNETIC FIELD FOR A GALACTIC DYNAMO 155 M.J. Rees

LARGE-SCALE MAGNETIC FIELD GENERATION IN GALAXIES BY DYNAMO PROCESSES 161 F. Krause

GAMMA RAY JETS AND BLACK HOLE MAGNETOSPHERES IN ACTIVE GALACTIC NUCLEI 171 R.D. Blandford

COSMICAL MAGNETISM 181 L. Mestel

Subject Index 213

List of Acronyms 215 PREFACE

Prof. Leon Mestel has been an inspiration to many to study the role of magnetism in the Cosmos. To mark the occasion of his retin'ment from the after 43 years in , several of his friends and former students decided to hold an advanced research workshop in his honour. NATO agreed to finance this venture which was held at the Institute of Astronomy at Cambridge. The scientific organizing committee was J. Landstreet, D. Lynden-Bell, F. Pacini, M.A. Rud0rman and N.O. Weiss and most leading experts on Cosmical magnetism agreed to come. We are particularly grateful to Lyman Spitzer who, ably helped by his wife Doreen, !!;ave the after dinner addre~s on how the goddess Astrophysica had foreseen Leon's achievements in classical Greek times. Not without regret we decided to maintain the homog0neity of the material and therefore could not cover Leon Mestel's major achievements in non-magnetic astronomy. His work on the cooling of white dwarfs, his understanding that degenerate hydrogen was a nuclear explosive since its pressure was almost independent of temperature and hence, his picture of supernovae, which is now more commonly applied to novae, his seminal understanding of the 'law' of galactic rotation and his work on the non-linear development of t hp anisotropies generated in gravitational collapse. This book records the primary invited review lectures which give a fine picture of what is known today of the magnetism of the Earth, the Sun, the stars, the interbtdlar gas, the Galaxy and the extragalactic nebulae. Subjects discussed range from dynamo thpory and magnetic reconnect ion with the associated sheet currents to the pinch effect and the jets associated with radio sources. The ")'-ray bursts and the ")'-ray jets from quasars share the high energy astrophysics scene with a fascinating review of the evolution of pulsar magnetic fidds. To make this book more affordable we have kppt it short so that it gives a good overview of what is known. It should therefore provide an up-to-date starting point for the next generation of magnetic astrophysicists. A companion volume of paper~ contrihut0d to the meeting which may have as much meat but contain more dptail and are less of a I'('vi0w nature has h0en separately produced and is available from tIll' Imtitute of Astronomy, Camhridge

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PARTICIPANTS

J.-J. Aly, Servis d'Astrophysique, C.E.N. Saclay, F-91191 Gif-sur-Yvette, France. T. Amari, Observatoire de Paris, Section d'Astrophysique, 92195 Meudon, France. J. Babel, Service d'Astrophysique, DAPNIA, F-9112a Gif-sur-Yvette, France. Dr G. Belvedere, Istituto di Astronomia, Citta Universitaria, 1-95125 Catania, Italy. R.D. Blandford, California Institute of Technology, Pasadena, CA 91125, U.S.A. J. Bouvier, Observatoire de Grenoble, PB 53X, F-38o.,p Grenoble Cedex, France. J.C. Carvalho, C/Valencia 489, 3" - la, 0.80.13 Barcelona, Spain. A.A. da Costa, Complexo 1- CEUTL, Inst. Superior Tecnico, 10.96 Lisboa Codex, Portugal. R.D. Davies, Jodrell Bank, Macclesfield, Cheshire SKll 9DL, U.K. J.-F. Donati, Dept. de Recherche Spatiale, Obs. de Paris, F-92195 Meudon Cedex, France. R. Ebert, Institut fur Astronomie £3 Astrophysik, Am Hubland, D-87aa Wurzburg, Germany. G.B. Field, Center for Astrophysics, 60. Garden Street, Cambridge, MA 0.2138, U.S.A. H.D. Greyber, 10.123 Falls Road, Potomac, MD 20.854, U.S.A. R.N. Henriksen, Queens Univ., Department of Physics, Kingston, ON, Canada K7L 3N6 J. Heyvaerts, Observatoire de Strasbourg, 11 rue de l'Universite, 670.0.0. Strasbourg, France. R. Hide, Hook Institute, Clarendon Lab., Parks Road, Oxford OXl 3PU, U.K. S. Horiuchi, National Astronomical Obs., Mizusawa-shi, Iwate-ken, 0.23 Japan. K.D. Kahn, Department of Astronomy, Univ. of Manchester, Manchester M13 9PL, U.K. A. Kakouris, Section of Astrophys. £3 Astron., National Univ. of Athens, Athens, Greece. F. Krause, Astrophysikalisches Institut, Stubenrauchstr. 26, D-O-1591 Potsdam, Germany. J. Landstreet, Dep. of Astronomy, Univ. of w. Ontario, London, ON, Canada N6A 3K7 D. Lynden-Bell. Institute of Astronomy, Madingley Rd., Cambridge, U.K. 1. Mestel, Astronomy Centre, Univ. of Sussex, Falmer, Brighton, BNl 9QH, U.K. F. Meyer, MPI fur Physik und Astrophysik, D-8a46 Garching bei Munchen, Germany. H.K. Moffatt, D.A.M.T.P., Silver Street, Cambridge, U.K. T. Montmerle, DAPNIA/SAp 91191 Gif-sur- Yvette Cedex, France. T. Ch. Mouschovias, Univ. of Illinois, Department of Astronomy, Urbana, IL 6180.1, U.S.A. J.P. Ostriker, Obs., Peyton Hall, Princeton, NJ 0.8544 U.S.A. B.E.J. Pagel, NORDITA, Blegdamsvej 17, DK-21aO Copenhagen a, Denmark. E.N. Parker, Lab. for Astrophys. £3 Space, Univ. of Chicago, Chicago, IL 60.637, U.S.A. J. Perdang, Institut d'Astrophysique, Univ. de Liege, B-42aa Cointe-Ougree, Belgium. E. Priest, Dept. of Mathem. £3 Computational Sciences, St. Andrews, Fife, KY16 9SS M.H.L. Pryce, 4754 West Sixth Avenue, Vancouver, BC, Canada V6T lC5 M.J. Rees, Institute of Astronomy. Madingley Rd., Cambridge. M.A. Ruderman, Physics Department, Columbia University, New York, NY 10.0.27, U.S.A. M. C. Sauty, D.A.E.C., Observatoire de Paris, 92195 Meudon Cedex, France. P. Scheuer, Dep. of Physics, Cavendish Laboratory, Madingley Road, Cambridge, U.K. D.W. Sciama, S.I.S.S.A., Strada Costiera 11,1-340.14 Trieste, Italy. H. Spruit, MPI fur Physik und Astrophysik, D-8a46 Garching bei Munchen, Germany. R.J. Tayler, Astronomy Centre, University of Sussex, Falmer, Brighton, BNl 9QH, U.K.

xi xii

K.C. Tsinganos, University of Crete, Department of Physics, P.O. Box 1527, Crete - Greece. J.P. Vallee, JCM Telescope Group, Herzberg Institute, Ottawa ON, Canada K1A OR6 N.O. Weiss, D.A.M. T.P., Silver Street, Cambridge, U.K. R. Wielebinski, MPI fUr Radioastronomie, Auf dem Hugel 69, D-5300 Bonn, Germany. E.G. Zweibel, Univ. of Colorado, Campus Box 391, Boulder, CO 80309, U.S.A.