The onset of eruptive flare energy release requires both a buildup of stored energy and a trigger for the release of that energy. This talk will review key models of how this storage and release occurs in solar eruptions, in particular for breakout eruptions and for torus instability eruptions. In both cases, the eruptions require the buildup of free magnetic energy in the form of sheared...
What happens in the solar atmosphere in the hours, minutes and seconds before a flare starts, and what is the relationship, spatial or otherwise, to the impulsive phase? Observational studies of flare onsets are relatively few compared to the later phases of a flare, but clearly we need to understand conditions both before and after the flare 'trigger' interval to be able to progress on...
The study of the localized plasma conditions before the impulsive phase of a solar flare can help us understand the physical processes that occur leading up to the main flare energy release. Here, we present evidence of a hot X-ray ‘onset’ interval of enhanced isothermal plasma temperatures in the range of 10-15 MK up to tens of seconds prior to the flare’s impulsive phase. This ‘hot onset’...
Solar flares are explosive space weather events that rapidly convert stored magnetic energy into bulk motion, plasma heating, and particle acceleration via magnetic reconnection. For eruptive flares, the free energy source is ultimately the highly sheared magnetic field of a filament channel above a polarity inversion line. During the flare, the shear field becomes the reconnection guide...
Current sheets play a key role in solar flares as they are the locations where magnetic energy is liberated through reconnection and is converted to other forms. Yet, their formation and evolution during the impulsive phase of a flare remain elusive. In this talk, we will report new observations of a current sheet formation and subsequent evolution in the early stages of a solar flare. In...
