Kinetic Theory of the Inner Magnetospheric Plasma , George V. Khazanov
Springer, New York, 2011. $199.00 (581 pp.). ISBN 978-1-4419-6796-1
The inner magnetosphere (IM) begins at an altitude of about 1000 km, above the ionosphere whose plasma is relatively cool, dense, and quiescent. The IM ends at roughly 6 Earth radii, below the vast outer magnetosphere whose plasma, at 1-100 keV, is much more energetic. Owing to the highly dynamic behavior of the regions that border and supply plasma to the IM—and to the inhomogeneous magnetic field lines that thread it—the plasma-velocity distributions in that region are often highly anisotropic and non-Maxwellian. Therefore, in formulating a theoretical description of the IM, kinetic theory is not just a choice— it is a must.
An internationally recognized and respected expert on the theory of space plasmas, George Khazanov understands the importance of kinetic theory. His latest text, Kinetic Theory of the Inner Magnetospheric Plasma , includes many of the techniques and results that he himself discovered and developed over an active and productive research career that has spanned four decades, the most recent one spent at NASA. The book comes on the heels of a halfcentury of spacecraft-based observations and related IM theoretical developments. In consolidating those, the book provides a comprehensive reference for researchers involved in upcoming spacecraft missions, such as NASA’s Radiation Belt Storm Probes to determine the Sun’s influence on the kinetics of electrons and ions in Earth’s radiation belts, and Canada’s Enhanced Polar Outflow Probe to study superthermal particle coupling between the ionosphere and the magnetosphere.
The first chapter gives a brief overview of near-Earth space, emphasizing the IM, its role in the larger geospace system, and its connections to the ionosphere and the outer magnetosphere. Chapters 2-4 develop the key tools of kinetic theory, wave-particle interactions, and the hydrodynamics of space plasma, respectively. With those opening chapters, the author sets in place the theoretical foundations needed to understand IM theory.
Chapter 5 provides a general analysis of superthermal electron populations. As the name implies, those electrons are significantly more energetic than the ambient ionospheric electrons that, due to collisions with the neutral atmosphere, exist in thermal equilibrium with it. Driven by UV photoionization, or by secondary ionization produced by energetic particle precipitation from the magnetosphere, superthermal electrons can be highly anisotropic or can have highly structured, and therefore potentially unstable, velocity-space distributions. The transport and stability of superthermal electrons is the kind of problem that demands a kinetic treatment, which it receives in Khazanov’s chapters 7 and 8.
Topics covered in other chapters include cold-plasma transport, the effect of photoelectrons on incoherent-scatter radar spectra, and the possible use of those spectra as ground-based diagnostics of the solar UV spectrum. The final two chapters focus on the basic physics of the energetic ions that make up the ring current in the IM and on associated plasma waves, respectively. Mathematical issues that are too detailed for the main body of the book are included in a series of short appendices. Although Kinetic Theory of the Inner Magnetospheric Plasma is rigorous and exhaustive in its coverage of topics relevant to IM theory, it also, through numerous and well-chosen references, keeps a close connection to observations.
The book is written in a direct and succinct style that makes it accessible and highly informative even to readers who are not experts in kinetic theory. However, it does assume that readers have a working knowledge of basic plasma physics, and some of its topics will likely be of interest only to specialists. Although some exercises appear in the early chapters, it is, by and large, not formatted as a textbook and would require supplementary materials for use in an academic course. It nicely complements the treatment of the IM found in Ionospheres: Physics, Plasma Physics, and Chemistry by Robert Schunk and Andrew Nagy (second edition, Cambridge University Press, 2009), which covers a broader range of space-physics topics, mostly at a less advanced level.
Overall, Kinetic Theory of the Inner Magnetospheric Plasma is a valuable and welcome addition that fills an important niche in the space plasma physics literature. With its broad selection of topics and balance between technical detail and context, the book will be a valuable reference for all researchers in the field of space physics and for specialists in plasma theory, in laboratory plasmas, and even in statistical physics and kinetic theory in general.
