Advances in Planetary Science Print ISSN: 2529-8054 Online ISSN: 2529-8062 Series Editor: Wing-Huen Ip (National Central University, Taiwan) The series on Advances in Planetary Science aims to provide readers with overviews on many exciting developments in planetary research and related studies of exoplanets and their habitability. Besides a running account of the most up-to-date research results, coverage will also be given to descriptions of milestones in space exploration in the recent past by leading experts in the field. Published Vol. 7 Neutral-Atom Astronomy: Plasma Diagnostics from the Aurora to the Interstellar Medium by Ke Chiang Hsieh and Eberhard Möbius Vol. 6 Ceres: An Ice-Rich World in the Inner Solar System by Jian-Yang Li and Julie C Castillo-Rogez Vol. 5 Mars on Earth: A Study of the Qaidam Basin edited by Long Xiao Vol. 4 Planetary Habitability in Binary Systems by Elke Pilat-Lohinger, Siegfried Eggl and Ákos Bazsó Vol. 3 Planetary Habitability and Stellar Activity by Arnold Hanslmeier Vol. 2 Origin and Evolution of Comets: Ten Years after the Nice Model and One Year after Rosetta by Hans Rickman Vol. 1 Nuclear Planetary Science: Planetary Science Based on Gamma-Ray, Neutron and X-Ray Spectroscopy by Nobuyuki Hasebe, Kyeong Ja Kim, Eido Shibamura and Kunitomo Sakurai JJoosseepphh -- 1111224411 -- NNeeuuttrraall--AAttoomm AAssttrroonnoommyy..iinndddd 11 1144//22//22002222 1100::2266::2222 aamm WWoorrlldd SScciieennttiifificc Published by World Scientific Publishing Co. Pte. Ltd. 5 Toh Tuck Link, Singapore 596224 USA office: 27 Warren Street, Suite 401-402, Hackensack, NJ 07601 UK office: 57 Shelton Street, Covent Garden, London WC2H 9HE Library of Congress Control Number: 2022932734 British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library. Advances in Planetary Science — Vol. 7 NEUTRAL-ATOM ASTRONOMY Plasma Diagnostics from the Aurora to the Interstellar Medium Copyright © 2022 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, including photocopying, recording or any information storage and retrieval system now known or to be invented, without written permission from 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 978-981-3279-19-3 (hardcover) ISBN 978-981-3279-20-9 (ebook for institutions) ISBN 978-981-3279-21-6 (ebook for individuals) For any available supplementary material, please visit https://www.worldscientific.com/worldscibooks/10.1142/11241#t=suppl Desk Editor: Joseph Ang Typeset by Stallion Press Email: [email protected] Printed in Singapore JJoosseepphh -- 1111224411 -- NNeeuuttrraall--AAttoomm AAssttrroonnoommyy..iinndddd 22 1144//22//22002222 1100::2266::2222 aamm April27,2022 11:4 Neutral-AtomAstronomy:PlasmaDiagnostics...-9inx6in b4577-fm pagev To the community of past, present, and future investigators in space-plasma research beyond the reach of spacecraft and those who wish to venture even farther. v B1948 Governing Asia TTTThhhhiiiissss ppppaaaaggggeeee iiiinnnntttteeeennnnttttiiiioooonnnnaaaallllllllyyyy lllleeeefffftttt bbbbllllaaaannnnkkkk BB11994488__11--AAookkii..iinndddd 66 99//2222//22001144 44::2244::5577 PPMM April27,2022 11:4 Neutral-AtomAstronomy:PlasmaDiagnostics...-9inx6in b4577-fm pagevii Preface We want this book to be a primer for those who wish to learn about the diagnostics of space plasmas beyond the reach of spacecraft by detecting and analyzing energetic neutral atoms (ENAs) emanating from afar. We hope it will spawn novel ideas and approaches that 1 could expand the investigations into new domains. LikeENAs,bothofuscrossedboundaries,albeitartificialones,to discover,learn,andteach.Eventually,ourjourneysconvergedandled us to writing this book to convey a message to a receptive audience. K. C. Hsieh learned from C. Y. Fan and J. A. Simpson at the 2 3 University of Chicago to detect H and He nuclei of galactic and solar origins in interplanetary space. At the University of Arizona, Fan inspired him to develop neutral-atom analyzers aiming at inter- planetary neutral atoms. G. Gloeckler and D. Hovestadt, who won his respect in Simpson’s group, led him to the time-of-flight (TOF) technique and to partake in SOHO HSTOF, which turned into the first heliospheric ENA sensor. D. M. Hunten, E. Keppler, H. Lauche, H. Rosenbauer, S. Grzedzielski, and W. I. Axford gave him advice and support in his early ENA research. Working with C. C. Curtis, D. S. Evans, J. L’Heureux, W.-H. Ip, Arne Richter, A. L. Broadfoot, B. R. Sandel, J. Giacalone, J. R. Jokipii, J. K´ota, K.-L. Shih, 1For a refresher on space-plasma physics, we refer to George J. Parks’ Physics of Space Plasma: An Introduction, 2nd Ed. (2003, Westview Press, Boulder, USA)andamoreadvancedtextbyThomasE.Cravens’Physics ofSolar System Plasmas (1997, Cambridge University Press, UK). vii April27,2022 11:4 Neutral-AtomAstronomy:PlasmaDiagnostics...-9inx6in b4577-fm pageviii viii Neutral-Atom Astronomy: Plasma Diagnostics M. A. Gruntman, M. Hilchenbach, A. Czechowski, D. Mitchell, S. Barabash, S. Orsini, and A. Milillo was most gratifying. The technical support from UA’s Physics Department greatly eased his writing of this book after retirement. E. M¨obius started with laboratory plasma physics, studying H. Alfv´en’s Critical Ionization Velocity together with A. Piel under the tutelage of H. Schlu¨ter and G. Himmel at the Ruhr Universita¨t Bochum. He then took a turn into space plasma physics at the Max-Planck-Institut fu¨rExtraterrestrischePhysik.InD.Hovestadt’s group, he built one of the first space-borne TOF spectrographs, the SULEICA sensor for the AMPTE mission, led by G. Haerendel and S. M. Krimigis. This sensor enabled the detection of interstellar + He pickup ions, whose interpretation succeeded in collaboration with G. Gloeckler, D. Hovestadt, F. M. Ipavich, B. Klecker, M. A. Lee, and M. Scholer. This pivotal find moved EM’s interest to the heliosphere-interstellar medium interaction. Now at the University of New Hampshire, he collaborated with P. Bochsler, M. Bzowski, S. Fuselier, A. B. Galvin, J. Geiss, G. Gloeckler, P. A. Isenberg, L. M. Kistler, B. Klecker, H. Kucharek, M. A. Lee, D. McComas, D. Rucinski, N. A. Schwadron, M. Wieser, and P. Wurz, among many others. After being invited by J. Geiss to co-lead with him the first Workshop at the International Space Science Institute (ISSI)on the heliosphere and the interstellar medium he led two ISSI Science Teams on the interstellar gas in the heliosphere. This effort has now come full circle with the ENA and interstellar flow sensors on IBEX and their implementation on IMAP. Together, we express our gratitude to the dedicated engineering teams at our own and collaborating institutions for their tireless efforts in developing and finalizing the novel instrumentation that enabled the pioneering observations. After our paths met, we deepened our appreciation of the significance of ENA diagnostics of space plasmas beyond the reach of spacecraft. We gladly accepted W.-H. Ip’s invitation to share our enthusiasm with future investigators and students of space plasmas throughthisbook.Wehopethereaderswillbenefit,aswehave,from the forerunners and collaborators in this field. April27,2022 11:4 Neutral-AtomAstronomy:PlasmaDiagnostics...-9inx6in b4577-fm pageix Preface ix We begin with defining “ENA”, where ENA-diagnostics are valuable, and end with forecasting where ENA-diagnostics might lead. Between these two bookends, we start with the discovery of ENAs in space and their early detection in near-Earth space, followed by the fundamental relations between the observed ENAs and the properties of the remote plasma whence they come. Then, we introduce the requirements for and the implementation of ENA instruments, followed by sample results from the Earth’s magne- tosphere, other planet atmospheres and magnetospheres, the outer heliosphere,andnearinterstellarspace.Withlowerenergythresholds for detection, ambient neutral atoms (ANAs) crucial for the birth of ENAs, enter the purview of detection and analysis under special conditions. To write this book, we choose sufficiency over completeness as our guide. We are incredibly grateful to the UNH graduate Plasma Physicsstudentsinspring2016 forprovidingaconstructivereviewof the emerging Chapter3 on thephysics of ENAs from theperspective of future users of the book, as a bonus homework assignment. We thank M.A. Lee, N.A. Schwadron,and R.Winslow for their feedback on the critical aspects of ENA analysis and the flow of the text. E. M¨obius appreciates greatly the support and inspiring atmosphere of ISSI during extended visits in 2018 and 2019, while preparing the draft of four book chapters. The history of heliospheric ENA research would be wanting without noting a little-known effort that benefitted both of us and led to significant international collaborations as we write. From 1984 to 1988, annual workshops on heliospheric-ENA physics were held, thrice in Poland, once in Gu¨nzburg and in Moscow. They facilitated meetings of researchers from Eastern Europe, the Soviet Union, and non-communist countries with minimal financial and political risks. Under the shadow of the Cold War, S. Grz¸edzielski of Poland, joined by H. Rosenbauer and H.-J. Fahr of West Germany, V. B. Baranov and M. A. Gruntman of the USSR, led this visionary undertaking. With the support from W. I. Axford, then President th of COSPAR, the 6 workshop became a COSPAR Colloquium held inWarsaw,19–22September1989,launchingtheCOSPARColloquia