Solar Flares

This chapter deals with solar flares, the first sporadic, short-duration events of solar activity discovered more than and a century and a half ago. Traditionally, solar flares were considered as a sudden, rapid increase in the brightness of a small area of the solar surface in white light, X-ray or EUV, lasting from a few to tens minutes. In a more general sense, solar flares are now assumed as the sudden release of magnetic energy in the solar atmosphere, manifested in emission in various parts of the spectrum of electromagnetic waves, flows of accelerated particles and plasma, shocks, etc. The energy released during a flare is most likely stored in the corona in the form of coronal electric currents long before the flare begins. The “standard flare model” was developed in the late 1970s. It includes an eruptive flux rope and a current sheet beneath it, where magnetic reconnection occurs, converting magnetic energy into other forms.