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Auroral plasma dynamics
1668
Book reviews
Stratospheric Ozone Depletion/UV-B Radiation in the Biosphere, Hilton Biggs R. and Joyner M. E. (Eds.), 1994, 358 pp. Springer-Verlag, D M 228 hb. ISBN 3-540-57810-2.
Auroral Plasma Dynamics, Lysak R. L. (ed), 1993, 291 pp., American Geophysical Union, $57 pb., ISBN 0-87590-0399.
This is a remarkably interdisciplinary book; it is also especially timely. It arose from a NATO Advanced Research Workshop held in June 1993 in Gainesville, Florida. The purpose was to assess the most recent data in several different scientific disciplines on changes of stratospheric ozone amounts, how these relate to changes in the flux of solar UV-B radiation (280~320 nm, 1.6% of the solar "constant") at ground level, and how both of these relate to biology and botany. The papers presented are of a review nature, yet up-todate, and there are also many abstracts giving the latest results. Unfortunately a large number of minor retyping errors crept in when the papers were prepared in their camera-ready form, but these do not hinder understanding. The papers are grouped into seven sections, the first of which deals with physics and chemistry. The subject covered in depth are: (i) the effects of increased UV-B fluxes on tropospheric chemistry, particularly the oxidising (or self cleaning) capacity of the atmosphere which involves the oxides of nitrogen, ozone and hydroxyl radicals, (ii) contributions to the greenhouse effect made by ozone and CFCs, and (iii) the thermophysical properties of environmentally acceptable refrigerants. Section two reviews i) the physiological changes in plants due to enhanced UV-B fluxes, such as decreased photosynthetic activity (which depends mainly on the flux at 40~700 nm), ii) experiments carried out in Southern Argentina and also under UV-emitting fluorescent lamps, and iii) UV-B induced damage to D N A molecules. Section three deals with the effects of enhanced UV-B fluxes on aquatic systems, both freshwater and marine (particularly reduced phytoplankton production rates and transmission through the shells of invertebrate species such as limpets). UV-B radiation and human health is the topic of section four. The suppression of functions of the immune system and the formation of skin cancers are but two effects. The next two sections are concerned with the crucial subject of instrumentation and measurements, for both agricultural and atmospheric purposes. Attention is focused particularly on spectroradiometers, and the results obtained at different geographical sites. The figure on p. 276 is instructive; it shows a log-lin plot of irradiance (ranging from 10 7 to 1 W m -2 nm 1) against wavelength (from 290 to 325 nm) measured with a Brewer spectrophotometer at 0.5 nm intervals at Toronto on 7 May 1994. The ten curves, at approximately 40 minute intervals, proceed from bottom left to top right, and cover half the area of the graph. In Canada now, a UV index ranging from 1 to 10 is broadcast with the daily weather forecast to increase awareness of how the population should protect itself from overexposure to the Sun. Modelling UV-B effects on plants, on freshwater and marine ecosystems, and on human non-melanoma skin cancers are carefully reviewed in section seven. There is a brief appendix, which I suspect is of late submissions. This book will be most useful to all who are concerned with the various effects of increased UV-B fluxes due to the depletion of stratospheric ozone.
The dynamic nature of the aurora is, perhaps, its most difficult feature, both to describe and to explain. This book, arising out of the Chapman conference held in Minneapolis in October 1991, does this as admirably as any book can. It focuses on developments, within the last decade or so, in our understanding of acceleration processes occurring on auroral flux tubes above the ionosphere, up to an altitude of 15,000 kin. The editor, in the preface, states: "In addition to establishing the parallel potential drop model for the primary auroral acceleration, recent results have shown many detailed features of the particle distributions which involve time-dependent currents and fields and interactions between waves and particles". I am inclined to take exception to the first part of this assertion, and I disapprove of diagrams with the U-shaped equipotentials of an electrostatic field, such as appear on pages 114, 135, 153 and 259, which stop at arbitrary points. However, I strongly agree with the second part, which emphasises the importance of time dependent phenomena in auroral processes. This book is a mine of new results, obtained from rockets, satellites and theoretical and modelling studies, and discussions of them. Highlights are stereoscopic images of the visible aurora taken from near Minneapolis by J. R. Winckler, false colour Viking images showing auroral transients and pulsations (R. D. Elphinstone et al.), field-aligned currents associated with velocity shears (L. A. Weiss et al.), laboratory studies (R. L. Stenzel, and M. E. Koepke et al.), electromagnetic ion cyclotron waves (M. Temerin et al., T. Chang and M. Andrr), electrostatic lower hybrid waves (R. L. Arnoldy), the ion-ion two stream instability (R. Bergmann et al.), auroral kilometric radiation (J. D. Menietti and J. L. Burch) and cavitons (R. Pottelette et al.). All auroral researchers should study this valuable source of information.
M. J. Rycroft Cranfield University
M. J. Rycroft Cranfield University
Satellite Geodesy, Seeber, Gunter, 1993, 531 pp. Walter de Gruyter, Berlin, hb, ISBN 3-11-012753-9. Before embarking upon a detailed reading of this b o o . a n English translation of an upgraded version of the German edition of 1989--the reader would be well-advised to dwell a little on the opening paragraphs of the Preface, especially noting the author's comment that 'the character o f the book falls somewhere between that o f a textbook and that o f a handbook '. This comment is readily illustrated in the contents of the chapter on Fundamentals, following immediately after the Introduction, where we find an overwhelming multiplicity of facts and definitions relating to coordinate systems and signal propagation. A preliminary reading of an appropriate text of spherical astronomy and time systems would certainly be of great benefit at this introductory stage. The third chapter, on Satellite Orbital Motion, is necessarily fairly extensive and ranges from Keplerian motion, through the two-body problem, to Lagrange's planetary equations, perturbations and techniques of numerical integration. Again, we find a bewildering leap from a sixth form level of understanding to undergraduate and post-graduate
Book reviews
Stratospheric Ozone Depletion/UV-B Radiation in the Biosphere, Hilton Biggs R. and Joyner M. E. (Eds.), 1994, 358 pp. Springer-Verlag, D M 228 hb. ISBN 3-540-57810-2.
Auroral Plasma Dynamics, Lysak R. L. (ed), 1993, 291 pp., American Geophysical Union, $57 pb., ISBN 0-87590-0399.
This is a remarkably interdisciplinary book; it is also especially timely. It arose from a NATO Advanced Research Workshop held in June 1993 in Gainesville, Florida. The purpose was to assess the most recent data in several different scientific disciplines on changes of stratospheric ozone amounts, how these relate to changes in the flux of solar UV-B radiation (280~320 nm, 1.6% of the solar "constant") at ground level, and how both of these relate to biology and botany. The papers presented are of a review nature, yet up-todate, and there are also many abstracts giving the latest results. Unfortunately a large number of minor retyping errors crept in when the papers were prepared in their camera-ready form, but these do not hinder understanding. The papers are grouped into seven sections, the first of which deals with physics and chemistry. The subject covered in depth are: (i) the effects of increased UV-B fluxes on tropospheric chemistry, particularly the oxidising (or self cleaning) capacity of the atmosphere which involves the oxides of nitrogen, ozone and hydroxyl radicals, (ii) contributions to the greenhouse effect made by ozone and CFCs, and (iii) the thermophysical properties of environmentally acceptable refrigerants. Section two reviews i) the physiological changes in plants due to enhanced UV-B fluxes, such as decreased photosynthetic activity (which depends mainly on the flux at 40~700 nm), ii) experiments carried out in Southern Argentina and also under UV-emitting fluorescent lamps, and iii) UV-B induced damage to D N A molecules. Section three deals with the effects of enhanced UV-B fluxes on aquatic systems, both freshwater and marine (particularly reduced phytoplankton production rates and transmission through the shells of invertebrate species such as limpets). UV-B radiation and human health is the topic of section four. The suppression of functions of the immune system and the formation of skin cancers are but two effects. The next two sections are concerned with the crucial subject of instrumentation and measurements, for both agricultural and atmospheric purposes. Attention is focused particularly on spectroradiometers, and the results obtained at different geographical sites. The figure on p. 276 is instructive; it shows a log-lin plot of irradiance (ranging from 10 7 to 1 W m -2 nm 1) against wavelength (from 290 to 325 nm) measured with a Brewer spectrophotometer at 0.5 nm intervals at Toronto on 7 May 1994. The ten curves, at approximately 40 minute intervals, proceed from bottom left to top right, and cover half the area of the graph. In Canada now, a UV index ranging from 1 to 10 is broadcast with the daily weather forecast to increase awareness of how the population should protect itself from overexposure to the Sun. Modelling UV-B effects on plants, on freshwater and marine ecosystems, and on human non-melanoma skin cancers are carefully reviewed in section seven. There is a brief appendix, which I suspect is of late submissions. This book will be most useful to all who are concerned with the various effects of increased UV-B fluxes due to the depletion of stratospheric ozone.
The dynamic nature of the aurora is, perhaps, its most difficult feature, both to describe and to explain. This book, arising out of the Chapman conference held in Minneapolis in October 1991, does this as admirably as any book can. It focuses on developments, within the last decade or so, in our understanding of acceleration processes occurring on auroral flux tubes above the ionosphere, up to an altitude of 15,000 kin. The editor, in the preface, states: "In addition to establishing the parallel potential drop model for the primary auroral acceleration, recent results have shown many detailed features of the particle distributions which involve time-dependent currents and fields and interactions between waves and particles". I am inclined to take exception to the first part of this assertion, and I disapprove of diagrams with the U-shaped equipotentials of an electrostatic field, such as appear on pages 114, 135, 153 and 259, which stop at arbitrary points. However, I strongly agree with the second part, which emphasises the importance of time dependent phenomena in auroral processes. This book is a mine of new results, obtained from rockets, satellites and theoretical and modelling studies, and discussions of them. Highlights are stereoscopic images of the visible aurora taken from near Minneapolis by J. R. Winckler, false colour Viking images showing auroral transients and pulsations (R. D. Elphinstone et al.), field-aligned currents associated with velocity shears (L. A. Weiss et al.), laboratory studies (R. L. Stenzel, and M. E. Koepke et al.), electromagnetic ion cyclotron waves (M. Temerin et al., T. Chang and M. Andrr), electrostatic lower hybrid waves (R. L. Arnoldy), the ion-ion two stream instability (R. Bergmann et al.), auroral kilometric radiation (J. D. Menietti and J. L. Burch) and cavitons (R. Pottelette et al.). All auroral researchers should study this valuable source of information.
M. J. Rycroft Cranfield University
M. J. Rycroft Cranfield University
Satellite Geodesy, Seeber, Gunter, 1993, 531 pp. Walter de Gruyter, Berlin, hb, ISBN 3-11-012753-9. Before embarking upon a detailed reading of this b o o . a n English translation of an upgraded version of the German edition of 1989--the reader would be well-advised to dwell a little on the opening paragraphs of the Preface, especially noting the author's comment that 'the character o f the book falls somewhere between that o f a textbook and that o f a handbook '. This comment is readily illustrated in the contents of the chapter on Fundamentals, following immediately after the Introduction, where we find an overwhelming multiplicity of facts and definitions relating to coordinate systems and signal propagation. A preliminary reading of an appropriate text of spherical astronomy and time systems would certainly be of great benefit at this introductory stage. The third chapter, on Satellite Orbital Motion, is necessarily fairly extensive and ranges from Keplerian motion, through the two-body problem, to Lagrange's planetary equations, perturbations and techniques of numerical integration. Again, we find a bewildering leap from a sixth form level of understanding to undergraduate and post-graduate