Solar Energetic Particles (2^nd Ed., 2nd ed. 2021)
A Modern Primer on Understanding Sources, Acceleration and Propagation
Lecture Notes in Physics Series, Vol. 978

This open access book serves as a concise primer introducing the non-specialist reader to the physics of solar energetic particles (SEP). It systematically reviews the evidence for the two main mechanisms which lead to the so-called impulsive and gradual SEP events. This second edition contains two completely new chapters discussing element abundances and shock waves, reflecting new theoretical, modeling, and observational results. Existing chapters have been substantially expanded or updated with additions placed in a broader context.

More specifically, the author discusses the timing of the onsets of SEPs, their longitude distributions, their high-energy spectral shapes, their correlations with other solar phenomena, as well as the all-important elemental and isotopic abundances. The book relates impulsive SEP events to magnetic reconnection in solar flares and jets. The concept of shock acceleration by scattering on self-amplified Alfvén waves is introduced, as is theevidence of reacceleration of impulsive-SEP material in the seed population accessed by the shocks in gradual events. The text then develops processes of transport of ions out to an observer. Finally, a technique to determine the source plasma temperature in both impulsive and gradual events is demonstrated.The author also mentions the role of SEP events as a radiation hazard in space and briefly discusses the nature of the main particle telescope designs that have contributed to most of the SEP measurements.

Preface.- Introducing the Sun and SEPs.- A Turbulent History.- Distinguishing the Sources.- Impulsive SEP Events.- Gradual SEP Events.- High Energies and Radiation Effects.- Measurements of SEPs.- Elemental Abundances and FIP: SEPs, The Corona and the Solar Wind.- Hydrogen Abundances and Shock Waves.- Summary and Conclusions.

Born and raised in South Florida, Don Reames received his university education, leading in 1964 to a PhD in Nuclear Physics, at the University of California at Berkeley.  He then joined a group at NASA’s Goddard Space Flight Center in Maryland using sounding rockets and balloons to study galactic cosmic rays and energetic particles from the Sun.  He subsequently used data from experiments on the Gemini, IMP, ISEE, Helios, Voyager, Wind and STEREO missions, as well as many related solar missions, to study those particles and their origins more extensively.  He retired from NASA in 2003 to assume an Emeritus position, but also soon joined the University of Maryland in College Park to become a Senior Research Scientist.  His honors include the 2012 George Ellery Hale Prize from the Solar Physics Division of the American Astronomical Society for his work on the composition and transport of solar energetic particles, and in 2001 he receivedGoddard’s John C. Lindsay Memorial Award for Space Science for his work with solar ³He-rich events.