About the Flare Problem

Abstract

The macroscopic and microscopic structures of flares are discussed, their relations to spots, to the photospheric magnetic fields and especially to the filaments (prominences) are reviewed. Flares are macroscopically located in a horizontal magnetic field, mostly occupying the dividing line of polarities or the line of vanishing longitudinal field. Flares often reach into regions of very small fields.

Arguments are presented, which make it unprobable that the flare energy is supplied from outside the Hα-volume. It seems furthermore improbable that the flare phenomenon is a macroscopic explosion or collapse. There is spectroscopic and other evidence for the existence of subtelescopic structures. The close relation between flares and filaments-both show a similar magnetic configuration-lets us suspect that the preflare activation of a filament and the resulting subtelescopic distortions and twistings of the associated magnetic field are the basic processes leading to a flare.