Table Of ContentElectromagnetic Waves Series 31
Ionospheric Radio I Ionospheric
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Ionospheric Radio replaces an earlier publication Ionospheric Kenneth Davies is a senior research scientist at the
Propogation and is aimed at professional scientists, engineers, and Space Environment Laboratory in Boulder, Colorado, and e
students who need an intermediate-level reference and/or text. Professor Adjoint in the Departments of Astrophysical, r
Students of aeronomy and radio wave propogation are introduced Planetary and Atmospheric Sciences and Electrical and i
to basic wave theory in absorbing, anisotropic and dispersive Computer Engineering at the University of Colorado. c
In 1988 he was appointed Guest Professor in the
media, and to the physics of production, loss and movement of
Department of Space Physics, Wuhan University, China.
plasma in the ionosphere in the presence of the geomagnetic field. Between August 1975 and August 1976 he held the R
Various radio techniques are described, and applications to the Webster Memorial Fellowship at the Physics Department a
interpretation of ionospheric structures and dynamics are presented. of the University of Queensland, Brisbane. Dr Davies
The application of ionospheric data to radio communications was chairman of the Electromagnetic Wave Propogation d
problems includes the use of numerical and physical models and Panel of the Advisory Group in Aerospace Research and
prediction techniques, and methods for calculating signal strengths Development, and Chairman of Commission G of the io
are presented. Topics include Earth-space propagation, ionospheric UpaSp-UerRsS aI.n Hde t wiso t hpere avuiotuhso rb oofo mkso oren tihoanno s1p3h0e rsicc ierandtiifoic Kenneth Davies
modification, ionospheric disturbances, propagation by scattering
propagation.
from plasma irregularities, topside sounding, and propagation on
frequencies from the extremely low to the super high. Reference
lists are extensive and a section of questions tests the reader’s
understanding of the material.
D
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The Institution of Engineering and Technology
www.theiet.org
0 86341 186 X
978-0-86341-186-1
IET ELECTROMAGNETIC WAVES SERIES 31
Series Editors: Professor PJ.B. Clarricoats
Professor Y. Rahmat-Samii
Professor J.R. Wait
Ionospheric
Radio
Other volumes in this series:
Volume 1 Geometrical theory of diffraction for electromagnetic waves, 3rd edition
G.L James
Volume 10 Aperture antennas and diffraction theory E.V. Jull
Volume 11 Adaptive array principles J.E. Hudson
Volume 12 Microstrip antenna theory and design J.R. James, P.S. Hall and C. Wood
Volume 15 The handbook of antenna design, volume 1 A.W. Rudge, K. Milne, A.D. Oliver
and P. Knight (Editors)
Volume 16 The handbook of antenna design, volume 2 A.W. Rudge, K. Milne, A.D. Oliver
and P. Knight (Editors)
Volume 18 Corrugated horns for microwave antennas PJ.B. Clarricoats and A.D. Oliver
Volume 19 Microwave antenna theory and design S. Silver (Editor)
Volume 21 Waveguide handbook N. Marcuvitz
Volume 23 Ferrites at microwave frequencies AJ. Baden Fuller
Volume 24 Propagation of short radio waves D.E. Kerr (Editor)
Volume 25 Principles of microwave circuits C.G. Montgomery, R.H. Dicke and E.M. Purcell
(Editors)
Volume 26 Spherical near-field antenna measurements J.E. Hansen (Editor)
Volume 28 Handbook of microstrip antennas, 2 volumes J.R. James and P.S. Hall (Editors)
Volume 31 Ionospheric radio K. Davies
Volume 32 Electromagnetic waveguides: theory and applications S.F. Mahmoud
Volume 33 Radio direction finding and superresolution, 2nd edition P.J.D. Gething
Volume 34 Electrodynamic theory of superconductors S.A. Zhou
Volume 35 VHF and UHF antennas R.A. Burberry
Volume 36 Propagation, scattering and diffraction of electromagnetic waves
A.S. llyinski, G. Ya.Slepyan and A. Ya.Slepyan
Volume 37 Geometrical theory of diffraction V.A. Borovikov and B.Ye. Kinber
Volume 38 Analysis of metallic antenna and scatterers B.D. Popovic and B.M. Kolundzija
Volume 39 Microwave horns and feeds A.D. Olver, PJ.B. Clarricoats, A.A. Kishk and L Shafai
Volume 41 Approximate boundary conditions in electromagnetics T.B.A. Senior and
J.L. Volakis
Volume 42 Spectral theory and excitation of open structures V.P. Shestopalov and
Y. Shestopalov
Volume 43 Open electromagnetic waveguides T. Rozzi and M. Mongiardo
Volume 44 Theory of nonuniform waveguides: the cross-section method
B.Z. Katsenelenbaum, L Mercader Del Rio, M. Pereyaslavets, M. Sorella Ayza and
M.K.A. Thumm
Volume 45 Parabolic equation methods for electromagnetic wave propagation M. Levy
Volume 46 Advanced electromagnetic analysis of passive and active planar structures
T. Rozzi and M. Farinai
Volume 47 Electromagnetic mixing formulas and applications A. Sihvola
Volume 48 Theory and design of microwave filters I.C. Hunter
Volume 49 Handbook of ridge waveguides and passive components J. Helszajn
Volume 50 Channels, propagation and antennas for mobile communications
R. Vaughan and J. Bach-Anderson
Volume 51 Asymptotic and hybrid methods in electromagnetics F. Molinet, I. Andronov
and D. Bouche
Volume 52 Thermal microwave radiation: applications for remote sensing
C. Matzler (Editor)
Volume 53 Principles of Planar Near-Field Antenna Measurements S. Gregson,
J. McCormick and C. Parini
Volume 502 Propagation of radiowaves, 2nd edition L.W. Barclay (Editor)
Ionospheric
Radio
Kenneth Davies
The Institution of Engineering and Technology
Published by The Institution of Engineering and Technology, London, United Kingdom
First edition © 1990 Peter Peregrinus Ltd
Reprint with new cover © 2008 The Institution of Engineering and Technology
First published 1990
Reprinted 1996,2008
This publication is copyright under the Berne Convention and the Universal Copyright
Convention. All rights reserved. Apart from any fair dealing for the purposes of research
or private study, or criticism or review, as permitted under the Copyright, Designs and
Patents Act, 1988, this publication may be reproduced, stored or transmitted, in any
form or by any means, only with the prior permission in writing of the publishers, or in
the case of reprographic reproduction in accordance with the terms of licences issued
by the Copyright Licensing Agency. Inquiries concerning reproduction outside those
terms should be sent to the publishers at the undermentioned address:
The Institution of Engineering and Technology
Michael Faraday House
Six Hills Way, Stevenage
Herts, SGI 2AY, United Kingdom
www.theiet.org
While the author and the publishers believe that the information and guidance given
in this work are correct, all parties must rely upon their own skill and judgement when
making use of them. Neither the author nor the publishers assume any liability to
anyone for any loss or damage caused by any error or omission in the work, whether
such error or omission is the result of negligence or any other cause. Any and all such
liability is disclaimed.
The moral rights of the author to be identified as author of this work have been
asserted by him in accordance with the Copyright, Designs and Patents Act 1988.
British Library Cataloguing in Publication Data
Davies, K.
Ionospheric radio.
1. Radio waves. Propogation of effects on ionosphere
I. Title
621.384T1
ISBN (10 digit) 0 86341 186 X
ISBN (13 digit) 978-0-86341-186-1
Printed in the UK by Short Run Press Ltd, Exeter
Reprinted in the UK by Lightning Source UK Ltd, Milton Keynes
Preface
This text replaces two earlier publications (Davies 1965, 1969). The older
material has been updated, and additional references have been included.
Several new topics are treated that were either omitted in the earlier publications
or treated in a limited fashion. These include, for example, Earth-space propa-
gation (Chapter 8), medium frequencies (Chapter 11), and ionospheric modifica-
tion (Chapter 14). Discussions of other topics have been considerably expanded,
for example, the discussion of modern ionospheric sounding techniques in
Chapter 4.
Although the book is intended primarily for scientists and engineers working
in the disciplines that involve effects of the ionosphere, it will also be of value
to teachers and students who require introduction to the subject. Questions have
been included for each chapter to test the reader's comprehension of the text.
I thank I. Ahl and M. Wiarda for their help in the preparation of the
typescript, J. Bankhead and J. Watterson of the Boulder Laboratories Library
for help in literature research, and L. Murdock for editing.
K. Davies
Space Environment Laboratory
Boulder, Colorado
May 1989
Acknowledgments
It is impossible to acknowledge everyone who has contributed to this book, but
special thanks are due to scientific colleagues who read the typescript of the
various chapters and gave valuable advice: Chapter 1, W.L. Flock; Chapter 2,
H. Leinbach; Chapter 3, A.K. Paul; Chapter 4, R. Conkright; Chapter 5, E.K.
Smith; Chapter 6, T.A. Croft; Chapter 7, R.F. Donnelly; Chapter 8, J.A.
Klobuchar; Chapter 9, J.A. Joselyn; Chapter 10, J.A. Ferguson; Chapter 11,
R.D. Hunsucker and J.C.H. Wang; Chapter 12, CM. Rush; Chapter 13, G.R.
Sugar; Chapter 14, T.B. Jones. X.-M. Liu, and C. Stubenrauch read the script
and made numerous valuable suggestions. These colleagues and many authors
and publishers have generously given permission for the reproduction of
published figures and/or provided material. Wherever appropriate, these have
been acknowledged in the text. I thank E. Hildner and J.R. Wait for their
encouragement during the process of publication.
Finally, my deepest appreciation goes to my wife Joyce Davies for proofread-
ing and other chores during the preparation of the typescript.
Contents
1 Characteristics of waves and plasmas 1
1.1 Historical introduction 1
1.2 The radio spectrum 1
1.3 Units and symbols 4
.3.1 Fundamental quantities 4
.3.2 Electromagnetic symbols 4
.3.3 Wave symbols 4
.3.4 Magneto-ionic symbols 5
.3.5 Plasma symbols 6
.3.6 Atmosphere symbols 6
.3.7 Geographic, geomagnetic, and solar symbols 6
.3.8 Ionospheric symbols 7
.3.9 Propagation symbols 7
1.4 Siome properties of propagation media 8
.4.1 Homogeneous and inhomogeneous media 8
.4.2 Isotropy and anisotropy 8
1.5 1>roperties of waves 9
.5.1 Plane waves 9
.5.2 Propagation in a dispersive medium 10
.5.3 Propagation in an anisotropic medium 12
.5.4 Wave packets 12
.5.5 Phase paths and packet paths 14
1.6 1electromagnetic waves 16
1.7 I*lasma properties 20
1.7.1 Plasma frequencies 20
11.7.2 Gyrofrequencies 21
1.8 1Motions of ions in crossed electric and magnetic fields 23
1.9 (Collisions 24
1.10 'fhe Debye length 25
1.11 1leferences 25
vhi Contents
2 Solar-terrestrial relationships 27
2.1 The solar-terrestrial system 27
2.2 The Sun 27
2.2.1 The quiet Sun 27
2.2.1.1 General features 27
2.2.1.2 Sunspots 28
2.2.1.3 Ionizing radiations 33
2.2.1.4 Solar radio emissions 34
2.2.2 The active Sun 34
2.2.2.1 Flares 34
2.2.2.2 Radio emissions 36
2.3 The interplanetary medium 38
2.3.1 The solar wind 38
2.3.2 The interplanetary magnetic field 38
2.4 The Earth's magnetic field 39
2.4.1 The dipole approximation 39
2.4.2 The real field 42
2.4.3 The magnetosphere 45
2.4.4 Magnetic variations 47
2.4.4.1 The quiet field 47
2.4.4.2 Magnetic disturbances 48
2.5 Magnetic indices 49
2.5.1 The K indices 49
2.5.2 The A indices 50
2.5.3 Auroral electrojet index AE 50
2.5.4 Equatorial D 51
st
2.5.5 Selected quiet and disturbed days 51
2.5.6 Bartels' 'musical scales' 51
2.6 The auroral zones 51
2.7 The plasmasphere 55
2.8 The Earth's atmosphere 57
2.8.1 Nomenclature 57
2.8.2 Pressure, density, and temperature variations 58
2.8.3 Chemical composition 59
2.9 Formation of ionized layers 60
2.9.1 Production 60
2.9.2 Ion loss and layer shapes 63
2.9.3 Transport of plasma 65
2.9.3.1 Plasma diffusion 65
2.9.3.2 Neutral winds 66
2.9.3.3 Electromagnetic drift 68
2.10 References 68
Contents ix
3 Magnetoionic theory 70
3.1 The Appleton formula 70
3.2 Some properties of the Appleton formula 73
3.2.1 With parallel propagation 74
3.2.2 With perpendicular propagation 75
3.3 Approximate formulas 77
3.4 Polarization 77
3.4.1 Polarization equations 77
3.4.2 Polarization ellipses 78
3.4.3 Polarization with vertical propagation 80
3.4.4 Transverse and longitudinal propagation 80
3.4.5 Effect of collisions 81
3.4.6 Limiting polarization 82
3.5 Coupling 83
3.6 Ray direction in a magnetoplasma 83
3.7 Effects of heavy ions 84
3.8 Generalized magnetoionic theory 84
3.8.1 Nature of electron collisions 84
3.8.2 Generalized complex refractive index 85
3.8.3 Limiting conditions 85
3.8.4 Frequency dependence of absorption 88
3.9 References 88
4 Radio soundings of the ionosphere 89
4.1 Introduction 89
4.2 Principles of measurement 89
4.2.1 Time of flight 89
4.2.2 Phase 90
4.2.3 Frequency variations 92
4.2.4 Polarization measurements 92
4.2.5 Angle of arrival 93
4.3 Ionosondes 93
4.3.1 Conventional ionosonde technique 93
4.3.2 Some limitations of conventional ionosondes 97
4.3.3 Monitoring versus research ionosondes 97
4.4 Some new sounders 98
4.4.1 The NOAA/HF sounder 98
4.4.2 The digisonde 100
4.4.3 The IPS-42 sounder 101
4.4.4 The chirp sounder 102
4.5 Modes of operation 105
4.6 Some disadvantages of ionosondes 105
4.7 Incoherent scatter sounders 106
4.8 Other techniques 111
4.8.1 Virtual height-time recorder 111
