Table Of ContentArtificial Particle
Beams in Space
Plasma Studies
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Artificial Particle
Beams in Space
Plasma Studies
Edited by
Bj(2)rn Grandal
Norwegian Defence Research Establishment
Kjeller, Norway
PLENUM PRESS. NEW YORK AND LONDON
Published in cooperation with NATO Scientific Affairs Division
Library of Congress Cataloging in Publication Data
NATO Advanced Research Institute on Artificial Particle Beams in Space Plasma Studies
(1981: Geilo, Norway)
Artificial particle beams in space plasma studies.
(NATO advanced study institutes series. Series B, Physics; v. 79)
"Proceedings of a NATO Advanced Research Institute on Artificial Particle Beams in
Space Plasma Studies, held April 21-26, 1981, in Geilo, Norway" - T.p. verso.
"Published in cooperation with NATO Scientific Affairs Division."
Includes bibliographical references and index.
\. Space plasmas-Congresses. 2. Particle beams-Congresses. I. Grandal, Bj(brn,
1948- . II. North Atlantic Treaty Organization. Division of Scientific Affairs. III.
Title. IV. Series.
QC809.P5N27 1981 530.4'4 82-470
AACR2
ISBN-13: 978-1-4684-4225-0 e-ISBN-13: 978-1-4684-4223-6
001: 10.1 007/978-1-4684-4223-6
Proceedings of a NATO Advanced Research Institute on Artificial Particle Beams
Utilized in Space Plasma Studies, held April 21 - 26, 1981, in Geilo, Norway
© 1982 Plenum Press, New York
Softcover reprint of the hardcover 1s t 1982
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No part of this book may be reproduced, stored in a retrieval system, or transmitted,
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PREFACE
These proceedings are based upon the invited review
papers and the research notes presented at the NATO
Advanced Research Institute on "Artificial Particle
Beams in Space Plasma Studies" held at Geilo, Norway
April 21-26, 1981.
In the last decade a number of research groups
have employed artificial particle beams both from
sounding rockets and satellites in order to study
various ionospheric and magnetospheric phenomena.
However, the artificial particle beams used in this
manner have given rise to a number of puzzling effects.
Thus, instead of being just a probe for studying the
ambient magnetosphere, the artificial particle beams
have presented a rich variety of plasma physics
problems, in parti~ular various discharge phenomena,
which in themselves are worthy of a careful study.
The experimental studies in space using artificial
particle beams have in turn given rise to both theore
tical and laboratory studies. In the laboratory experi
ments special attention has been paid to the problem of
creating spacelike conditions in the vacuum chamber.
The theoretical. work has addressed the question of beam
plasma-neutral interaction with emphasis on the wave
generation and the modified energy distributions of the
charged particles. Numerical simulations have been used
extensively.
With the advent of the Space Shuttle in which
several artificial particle beam experiments are
planned for the 1980's, there is a growing interest in
such experiments. Furthermore, there is a need for
coordinating these studies, both in space and in the
laboratory.
v
vi PREFACE
This book contains a broad review of recent ex
periments both in space, Chapter 1, and in the labora
tory, Chapter 3. Chapter 2 is devbted to a brief
discussion of the natural particle beams in space.
Recent theoretical work, with emphasis on the beam
plasma-discharge (BPD) is given in Chapter 4. The
present understanding of the charging and neutralization
processes in the vicinity of a space vehicle employing
particle accelerators is outlined in Chapter 5.
At the end of chapters 1, 3 and 5, summaries of the
general discussions at the respective sessions of the
meeting are given. The subject matter covered in these
general discussions does overlap and no attempt has been
made to sort out the related topics. These summaries,
included to give the reader an impression of the issues
of interest, are written by the editor, based on notes
taken by T Hallinan, N Kawashima and himself.
Chapter 6 includes a summary of the final discus
sions with future plans, written by B N M~hlum, and a
few of the contributed papers outlining future work.
At the end of most of the papers, selected questions
of general interest are included.
The responsibility for the uneven coverage of some
of the topics lies with the editor and the program
committee, rather than with the individual contributors.
The editor would like to express his gratitude to
B N M~hlum for his constant support.
Kjeller, July 1981
Bj¢rn Grandal
DIRECTOR'S PAGE
Bernt N Maehlum, Program Director
Several studies of beam-plasma interactions have
been conducted in space and in laboratory plasma
chambers in recent years. Also, particle accelerators
on rockets and satellites have been used for probing
the ionosphere and magnetosphere.
This work has resulted in several publications,
but it is well known that many results from similar
studies have not yet been presented in the literature
due to apparent lack of consistency.
During the NATO-ARI several unexplained and
unpublished observations were presented, and I per
sonally feel that a somewhat coherent picture is now
emerging from the apparent confusion. It is hoped that
the results from the meeting may serve as a platform
for future activity in the field.
Let me acknowledge the assistance given me by
the program committee: Drs C Beghin, W Bernstein,
A Johnstone, L M Linson and J R Winckler. Without their
help we could not have organized the meeting.
Also, an active organizing committee, consisting
of Drs B Grandal, J Holtet and T A Jacobsen, have taken
their share of the work.
Finally, let me thank the secretary, Mrs E Kurland,
who kept track of all the loose papers before, during
and after the conference.
In addition to the NATO grant which covered most of
the expenses, some financial support was obtained from
the Royal Norwegian Council for Scientific and
Industrial Research and the Norwegian Defence Research
Establishment.
VII
OPENING SPEECH
Bjl/lrn Landmark
Royal Norwegian Council for Scientific and Industrial
Research
Oslo, Norway
Twenty years ago, in 1961, a group of ionospheric physicists
at the Norwegian Defence Research Establishment arranged the first
NATO Advanced Study Institute in Norway at a remote mountain hotel.
The title of the Institute was "Electron Density Profiles in the
Ionosphere and Exosphere", and the meeting was successful partly
because the right people were present and partly because it was
arranged at a secluded place with ample opportunities for the parti
cipants to meet during leisure hours at the hotel and on the ski
slopes for informal discussions.
Two years later a new NATO ~eeting was arranged at the same
hotel. This time the topic of the conference was "Electron Density
Profiles in the Ionosphere and Exosphere". This was also a success
ful meeting, and it was followed by a third meeting in 1965, which
again was devoted to "Electron Density Profiles in the Ionosphere
and Exosphere".
After these three initial meetings with the same "winning
title", six more NATO Advanced Study Institutes have been arranged
on Upper Polar Ionosphere and Space Plasma problems. All of these
have had a fairly broad scope. In fact, the one last year was en
titled "Exploration of the Polar Upper Atmosphere".
The meeting which starts here today is therefore number ten
in the series of NATO conferences in Norway, which calls for a cele
bration. In contrast to the previous Institutes the format of this
meeting is so specialized that the NATO Science Committee initially
declined to fund it under the Advanced Study Institute program.
However, the committee turned around and established a new series
of conferences, named NATO Advanced Research Institutes. As we
ix
x OPENING SPEECH
understand it, the future of the Research Institute program depends
largely on the success of the present meeting. Therefore, we need
to work hard to keep this program going.
All the previous NATO Advanced Institutes in Norway on upper
atmosphere and magnetospheric phenomena are based on passive ob
servations of the natural phenomena. Also, due to the geographical
location of Norway emphasis has been placed on high latitude, au
roral problems.
The present meeting on the other hand, will mainly be con
cerned with various methods for artificial modification of the
upper atmosphere in order to study, under controlled conditions,
the various beam-plasma interactions in space, such as those taking
place in the auroral ionosphere. The first attempt made for pro
ducing artificial auroras in the laboratory was conducted early
this century by the Terrellas, and as you know - my countryman
Kr Birkeland - was one of the pioneers in this field. His Terrellas
are on display in the Technical Museum in Oslo if you would like to
see them. Some 50 years later the first artificial aurora in the
upper atmosphere was created on a rocket launched some ten years
ago by Wilmot Hess and his colleagues.
Strangely enough, during the last 5-6 years, when this field
has been rapidly expanding, the interest for generation for arti
ficial auroras is no longer the main driving force. The particle
beams are now mostly used as diagnostic tools for studying iQnos
pheric and magnetospheric plasma processes, such as plasma heating
by fast particle beams, scattering or fast electrons in a plasma,
tracing of geomagnetic field lines, enhancements in the plasma den
sity, wave generation through beam-plasma interactions, detection
of electric double layers etc. It is not quite clear yet how many
of these studies that will contribute to a deeper understanding of
the auroral processes, since the current density in most of the
particle beam experiments generally exceeds the natural auroral
particle fluxes by orders of magnitude. However, the studies of
upper atmosphere beam-plasma interactions per se give important
results from a plasmaphysics point of view. I believe that also
some astrophysical problems may be elecidated by these experiments.
As a complement to the space plasma studies by particle beams,
several laboratory experiments have been conducted in recent years.
These have given valuable information on the energy dissipation
processes. It has been'demonstrated how the instabilities which
occurs for certain beam currents and plasma densities may enhance
the transfer rate of energy from the beam to the plasma. We will
hear more about results from these studies at the conference.
The new observations of the beam-plasma interaction in the
laboratory and in space have created some interest among theoreti-
OPENING SPEECH xi
cians, and there is now a fruitful exchange of ideas between ex
perimentalists and the theoreticians in the field. A session at
this conference is devoted to theoretical studies of the beam
plasma interaction.
Among the applied aspects of this field are the problems re
lated to space vehicle neutralization in the ionosphere. Several
groups are involved in studies of this problem, and a series of
papers will present us with the state of art.
One of the main aims of the meeting is to bring workers from
different but related fields together for informal discussions of
problems of joint interest. Also, during the last session future
plans and possible recommendations for new and cooperative experi
ments will be discussed. I feel that both from a scientific and
from an economic point of view international cooperation is im
portant, and it is my hope that this meeting will contribute to
a continued growth in the field. Future Space labs and rocket
flights open up new opportunities, and it is hoped that the plans
for closing the large plasma chamber at Johnson Space Center will
not spread to other facilities. There are still a number of pro
blems to be solved in the laboratory.
