J. Brit. Astron. Assoc., 106, 6, 1996, p. 344
John Wiley/Praxis Publishing, 1996. ISBN 0-471-96023-3 (hbk); 0-471-96024-1 (pbk). Pp xiii + 172, £19.99 (pbk).
reviewed by D. A. R. Simmons
The Aurora: Sun–Earth Interactions is an excellent and comprehensive general discussion of present-day knowledge of the aurora and of the geophysical basis of the Sun–Earth relationships that underlie auroral phenomena. The author, one of Britain's most dedicated amateur astronomers, is well-known for his published work in auroral and meteor sciences. He is therefore well qualified for the task he has set himself.
The book seems certain to become a 'must' for all auroral observers and possibly for other amateur astronomers as well. It should also be useful to undergraduate and postgraduate scientists in physics, astronomy and geophysics as an overview of the field before launching into the more specialised scientific literature.
The book is written in a clear, simple style that makes for easy, compulsive reading. The introductory and historical chapters cover much the same ground as earlier texts but with a freshness that makes them most readable. The sections on early scientific investigations are well described in a chronological sequence that emphasises the development of our ideas about the aurora. The chapter on the Sun gives a good general description of flares, the chromosphere, the solar wind and the heliosphere – all useful background information but not specifically correlated with the aurora. The section on the Earth's Magnetosphere deals with terrestrial magnetism, the magnetosphere, the auroral ovals, interactions with the solar wind, geomagnetic storms, coronal holes and disappearing filaments. It also includes a summary of planetary aurorae with interesting photographs of jovian and saturnian events taken with the Hubble Space Telescope.
All these features are described with commendable clarity except for two occasions. In Fig. 5.2 (p.69), the direction of the cross-tail (dawn-dusk) east-west current is not apparent as the diagram is not adequately labelled, and no statement is made as to the direction from which the cross-section is viewed (sunward or anti-sunward). Similarly, the sentences describing the effect of the Lorentz force (p.69) on charged particles in a magnetic field are ambiguous and the direction of movement (a right-handed helix for negative ions and a left-handed helix for positive ions along the local field-line as guiding centre) is not stated.
The remaining chapters are little altered from the first edition. This was probably a wise decision since they contain much practical information about auroral observing, photography and simple magnetometry that is useful for amateurs. The last chapter in the book, 'Related high atmosphere phenomena', is dedicated mainly to noctilucent cloud and the night airglow. Although the aurora and noctilucent cloud are not geophysically related, the inclusion of noctilucent cloud can be justified as the techniques for investigating both phenomena are very similar – at least for the amateur. Moreover, observing noctilucent cloud is good occupational therapy for observers denied sight of the aurora during the long summer twilights at high latitudes!
The addition of a glossary and a comprehensive index are welcome features of the new book which is well-illustrated with helpful diagrams and interesting photographs. The book is well produced and almost free from typographical and other errors. It can be recommended wholeheartedly as a worthwhile acquisition for one's bookshelves.
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