Short Historical Overview In the 1940s, two phenomena in the ?eld of cosmic rays (CR) forced scientists to think that the Sun is a powerful source of high-energy particles. One of these was discovered because of the daily solar variation of CR, which the maximum number of CR observed near noon (referring to the existence of continuous ?ux of CR from the direction of the Sun); this became the experimental basis of the theory that CR’s ́ originate from the Sun (or, for that matter, from within the solar system) (Alfven 1954). The second phenomenon was discovered when large ?uxes of high energy particles were detected from several solar ?ares, or solar CR. These are the - called ground level events (GLE), and were ?rst observed by ionization chambers shielded by 10 cm Pb (and detected mainly from the secondary muon-component CR that they caused) during the events of the 28th of February 1942, the 7th of March 1942, the 25th of July 1946, and the 19th of November 1949. The biggest such event was detected on the 23rd of February 1956 (see the detailed description in Chapters X and XI of Dorman, M1957). The ?rst phenomenon was investigated in detail in Dorman (M1957), by ?rst correcting experimental data on muon temperature effects and then by using coupling functions to determine the change in particle energy caused by the solar-diurnal CR variation.

Short Historical Overview In the 1940s, two phenomena in the ?eld of cosmic rays (CR) forced scientists to think that the Sun is a powerful source of high-energy particles. One of these was discovered because of the daily solar variation of CR, which the maximum number of CR observed near noon (referring to the existence of continuous ?ux of CR from the direction of the Sun); this became the experimental basis of the theory that CR’s ́ originate from the Sun (or, for that matter, from within the solar system) (Alfven 1954). The second phenomenon was discovered when large ?uxes of high energy particles were detected from several solar ?ares, or solar CR. These are the - called ground level events (GLE), and were ?rst observed by ionization chambers shielded by 10 cm Pb (and detected mainly from the secondary muon-component CR that they caused) during the events of the 28th of February 1942, the 7th of March 1942, the 25th of July 1946, and the 19th of November 1949. The biggest such event was detected on the 23rd of February 1956 (see the detailed description in Chapters X and XI of Dorman, M1957). The ?rst phenomenon was investigated in detail in Dorman (M1957), by ?rst correcting experimental data on muon temperature effects and then by using coupling functions to determine the change in particle energy caused by the solar-diurnal CR variation.

This book consists of a selection of original papers of the leading scientists in the fields of Space and Planetary Physics, Solar and Space Plasma Physics with important contributions to the theory, modeling and experimental techniques of the solar wind exploration. Its purpose is to provide the means for interested readers to become familiar with the current knowledge of the solar wind formation and elemental composition, the interplanetary dynamical evolution and acceleration of the charged plasma particles, and the guiding magnetic field that connects to the magnetospheric field lines and adjusts the effects of the solar wind on Earth. I am convinced that most of the research scientists actively working in these fields will find in this book many new and interesting ideas.

Presents a comprehensive approach to the open questions in solar cosmic ray research and includes consistent and detailed considerations of conceptual, observational, theoretical, experimental and applied aspects of the field. The results of solar cosmic ray (SCR) investigations from 1942 to the present are summarized in this book. It treats the research questions in a self-contained form in all of its associations, from fundamental astrophysical aspects to geophysical, aeronautical and cosmonautical applications. A large amount of new data is included, which has been accumulated during the last several decades of space research. This second edition contains numerous updates and corrections to the text, figures and references. The author has also added several new sections about GLEs and radiation hazards. In addition, an extensive bibliography is provided, which covers non-partially the main achievements and failures in the field. This volume is aimed at graduate students and researchers in solar physics and space science.