The sun being our nearest star, is the only one which astronomers can examine at sufficiently close range to resolve spatial features. However, the complex processes of particle acceleration and energy release happen even more dramatically elsewhere. It therefore follows that the better we understand the sun, the more insight we have of activity in other stars. Solar flares , which are the basis of our models of stellar flares, are a complex phenomenon and there is as yet no detailed description of the physical processes involved with which everybody will agree. Nevertheless, certain details are becoming increasingly clear.
Many flares occur within complexes of magnetic fields called active regions.
Most will agree that a flare occurs when an instability develops in one or more magnetic loops which requires the magnetic configuration to rearrange itself. As a by-product of this rearrangement, magnetic energy is released. This energy may either produce local heating in the vicinity of the instability or, as seems more likely on the basis of recent evidence, it may either accelerate a beam of non-thermal electrons or generate a conduction front. The electrons in such circumstances would be constrained to move parallel to the magnetic lines of force i.e. along the axis of the magnetic loop. The density of matter in the corona, where the bulk of the loop exists, is sufficiently low for the electrons to travel relatively unimpeded.