This book describes physical conditions in the upper atmosphere and magnetosphere of the Earth.

Earth-affecting solar transients encompass a broad range of phenomena, including major solar flares, CMEs, ICMEs, solar energetic particle events, and corotating interaction regions.​ In the past decade, nearly continuous observations of the Sun and the inner heliosphere with an unprecedented wide spatial coverage from a fleet of spacecraft, including STEREO Ahead/Behind, SDO, SOHO, Messenger, Venus Express, ACE and WIND, in combination with a significant advancement of global MHD numerical simulation and theoretical analysis, have greatly improved our understanding of solar transients and the prediction of their potential impact on Earth. This Topical Collection is based on the International Study of Earth-affecting Solar Transients (ISEST) project, initially launched in 2013 to bring together scientists from many countries to join efforts on studying solar transients. ISEST became one of the four research projects of the Variability of the Sun and Its Terrestrial Impact (VarSITI) program, sponsored by the Scientific Committee on Solar-Terrestrial Physics (SCOSTEP) for the period of 2014 – 2018. Originally published in the journal Solar Physics, volumes 292 (2017) and 293 (2018).

This books presents a brief review of modern concepts of the Sun-Earth problem and proposed physical mechanisms of solar-terrestrial relations (STR). This field covers a wide range of fundamental and actual applied problems of paramount importance (Space Weather, radiation hazard in space, functioning of space-borne and ground-based technological systems, heliobiology etc.). It is also closely tied with some general gnosiological problems. The author provides state-of-the-art information about existing problems and discusses different channels for extraterrestrial influences at the up-to-date level: electromagnetic waves and fields, total solar irradiance, solar wind, energetic solar particles, galactic cosmic rays, cosmic dust, etc. Some of the well-known and suggested STR effects and corresponding physical mechanisms are illustrated by several examples. In particular, a number of different external “signals” in observed changes of terrestrial climate and weather are considered. Especially, an expected impact of geophysical disturbances on the accuracy of some precise physical measurements and experiments is analysed. Due attention is paid to the heliobiological aspects of STR. Particular emphasis is on the multifactor nature of magneto-biological effect (MBE), its non-stationary and non-linear behaviour. The author also discusses main features of different physical mechanisms (electromagnetic fields, ionising radiation, triggers, rhythmic and resonances in solar-terrestrial systems) and their applicability to the Sun-Earth problem. The most of them are still needed in more sophisticated theoretical development and experimental confirmation. The main goals of interdisciplinary studies in this field are to determine partial impacts of solar-geomagnetic variability on the terrestrial environments and estimate (separate) relative contributions of different factors into various STR phenomena. The book is based on lectures given on advanced undergraduate level and will also benefit newcomers (physicists and engineers) to the field.