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Earth's magnetospheric processes
1822
BOOK REVIEWS
by reference to recent and impending satellite launchings (e.g. the OSO’s and OAO’s). The text is in fact developed to give the bare essentials for understanding the objectives and results of the satellite work. There is a little more here for the experimentalist, the principles of X-ray and y-ray detectors being discussed and some results presented. The brief review of stellar evolution, starting inevitably with the H-R diagram and ending with cosmological questions and intriguing ‘black holes’ is concise and informative. This is a good book for students to work through. The first six chapters are essentially the material covered in a &e-semester course on space physics which the author has given for several years at Boston University and is all good basic stuff, well presented. A book of this kind cannot treat in great depth the many areas it covers, so the author has quite sensibly provided a bibliography with each chapter. G. V. GROVES B. M. MCCORMAC (Editor): Earth’s Magnetospheric Processes. Reidel, Dordrecht, 1972. viii + 417. Dfl. 115. U.S. $ 37.50
Holland,
Billy McCormac has held a number of prestigious summer schools and been editor of proceedings therefrom. In the present volume he has again performed with the skill we have come to expect. We might, of course, interject the usual complaints, and claim that the volume is too expensive and that it took too long to get to press. Actually the price is in line with what other publications of conference proceedings demand, especially when they offer such a professional job of printing. Several figures are even in colour. And for a conference in late 1971 to appear in published form in 1972 is a tribute to the editor. I will not run through the table of contents (the title is self-explanatory) except to note that a reasonable balance is achieved between theory and observation. The volume opens with review papers, all excellent, and then continues on to shorter special interest papers, a mixed bag as always. One of the more interesting sections is the clear and concise summary by McCormac, wherein the long battle between the ‘open’ and ‘closed’ magnetospheric models is declared over and the former the winner. For those who do not understand the distinction, yet are inexplicably reading this review, let me briefly explain that in the closed model the geomagnetic field is confined by the solar wind, albeit some field lines are elongated to form a tail of indefinite length, whereas in the open model these tail field lines all connect as rapidly as possible to the magnetic field lines in the solar wind. No one doubts that some reconnection occurs. The debate centers on which limit is closer to nature; no reconnection = closed, or rapid reconnection = open. As an avowed proponent of the ‘closed’ magnetosphere, I have mixed feelings about McCormac’s pronouncement. One might grouse that the seeming unanimity in favor of open models is simply a selection effect (i.e. apologists were not invited), but actually it seems a healthy step. The great defect of the closed models was that they were predictive, in particular it was difficult to get particles from outside to inside the magnetosphere. Observation showed that while sometimes particle access took a long time, it was often quite rapid. The virtue of the open models was (and is) that they have not been worked out in detail, hence are more difficult to refute. A few of us still remain hesitant to adopt the open model simply because we do not know what it is. As McCormac points out, even proponents of the open model often draw the magnetopause as being closed, which it would not be in that model. Now that energy is no longer being diverted into deciding which model is correct, we can look forward to finding out what it is that is correct about the correct model. Another recent development worth noting is the popularity of magnetic ‘bubbles’ in the geomagnetic tail. It is difficult to feign enthusiasm for the concept (a relic of early work on the instability of geometrically flat magnetic neutral sheets in a plasma), but the reader can judge for himself. In any event, we have a new topic of controversy. Finally, we note that the Stockholm school is, for once, well represented. Much more is said about parallel electric fields, sheath effects, and double-layers than previously. Again, a healthy step and another reason why this book is a worthwhile acquisition for both the student and researcher of magnetospheric phenomena. F. CURTB MICHEL ZDENEKKOPAL: The Solar System. Oxford University Press. 1973. viii + 152. f2.25 (also in OPUS paperback edition at El *OO). Professor Kopal’s earlier writings on the solar system have mainly been concerned with the Moon. This new book, however, is intended to present a brief overview of our knowledge of the entire solar system in the light of recent advances, especially in radio astronomy and space research. For the most part, he provides a reliable, though necessarily highly compressed, account of the current position; but, inevitably, text already requires in certain respects-the description of the Martian surface, for example-the modification.
BOOK REVIEWS
by reference to recent and impending satellite launchings (e.g. the OSO’s and OAO’s). The text is in fact developed to give the bare essentials for understanding the objectives and results of the satellite work. There is a little more here for the experimentalist, the principles of X-ray and y-ray detectors being discussed and some results presented. The brief review of stellar evolution, starting inevitably with the H-R diagram and ending with cosmological questions and intriguing ‘black holes’ is concise and informative. This is a good book for students to work through. The first six chapters are essentially the material covered in a &e-semester course on space physics which the author has given for several years at Boston University and is all good basic stuff, well presented. A book of this kind cannot treat in great depth the many areas it covers, so the author has quite sensibly provided a bibliography with each chapter. G. V. GROVES B. M. MCCORMAC (Editor): Earth’s Magnetospheric Processes. Reidel, Dordrecht, 1972. viii + 417. Dfl. 115. U.S. $ 37.50
Holland,
Billy McCormac has held a number of prestigious summer schools and been editor of proceedings therefrom. In the present volume he has again performed with the skill we have come to expect. We might, of course, interject the usual complaints, and claim that the volume is too expensive and that it took too long to get to press. Actually the price is in line with what other publications of conference proceedings demand, especially when they offer such a professional job of printing. Several figures are even in colour. And for a conference in late 1971 to appear in published form in 1972 is a tribute to the editor. I will not run through the table of contents (the title is self-explanatory) except to note that a reasonable balance is achieved between theory and observation. The volume opens with review papers, all excellent, and then continues on to shorter special interest papers, a mixed bag as always. One of the more interesting sections is the clear and concise summary by McCormac, wherein the long battle between the ‘open’ and ‘closed’ magnetospheric models is declared over and the former the winner. For those who do not understand the distinction, yet are inexplicably reading this review, let me briefly explain that in the closed model the geomagnetic field is confined by the solar wind, albeit some field lines are elongated to form a tail of indefinite length, whereas in the open model these tail field lines all connect as rapidly as possible to the magnetic field lines in the solar wind. No one doubts that some reconnection occurs. The debate centers on which limit is closer to nature; no reconnection = closed, or rapid reconnection = open. As an avowed proponent of the ‘closed’ magnetosphere, I have mixed feelings about McCormac’s pronouncement. One might grouse that the seeming unanimity in favor of open models is simply a selection effect (i.e. apologists were not invited), but actually it seems a healthy step. The great defect of the closed models was that they were predictive, in particular it was difficult to get particles from outside to inside the magnetosphere. Observation showed that while sometimes particle access took a long time, it was often quite rapid. The virtue of the open models was (and is) that they have not been worked out in detail, hence are more difficult to refute. A few of us still remain hesitant to adopt the open model simply because we do not know what it is. As McCormac points out, even proponents of the open model often draw the magnetopause as being closed, which it would not be in that model. Now that energy is no longer being diverted into deciding which model is correct, we can look forward to finding out what it is that is correct about the correct model. Another recent development worth noting is the popularity of magnetic ‘bubbles’ in the geomagnetic tail. It is difficult to feign enthusiasm for the concept (a relic of early work on the instability of geometrically flat magnetic neutral sheets in a plasma), but the reader can judge for himself. In any event, we have a new topic of controversy. Finally, we note that the Stockholm school is, for once, well represented. Much more is said about parallel electric fields, sheath effects, and double-layers than previously. Again, a healthy step and another reason why this book is a worthwhile acquisition for both the student and researcher of magnetospheric phenomena. F. CURTB MICHEL ZDENEKKOPAL: The Solar System. Oxford University Press. 1973. viii + 152. f2.25 (also in OPUS paperback edition at El *OO). Professor Kopal’s earlier writings on the solar system have mainly been concerned with the Moon. This new book, however, is intended to present a brief overview of our knowledge of the entire solar system in the light of recent advances, especially in radio astronomy and space research. For the most part, he provides a reliable, though necessarily highly compressed, account of the current position; but, inevitably, text already requires in certain respects-the description of the Martian surface, for example-the modification.