June 18, 2010, 12:00 pm - 1:00 pm

June 18, 2010, 12:00 pm - 1:00 pm

Before and after: What can subsurface flows and coronal dimmings tell us about CME/flare initiation and early evolution

Alysha Reinard (NOAA)

Solar flares and CMEs are closely associated with one another and are presumably caused by a buildup of energy in the corona, but the precise details are not well understood. By analyzing the precursors of an eruption and the immediate aftermath, we can begin to probe the details of CME and flare initiations. Helioseismology measurements of specific subsurface motions have recently been linked to flaring activity. In particular, strong, rapidly decreasing subsurface twisting has been observed 2-3 days prior to the occurrence of a flare. This signature is stronger for larger flares, indicating that these motions contribute to the energy available for the event. Coronal dimmings, which occur directly following a CME, represent plasma that has been removed from the corona by an eruption. Dimming associated CMEs have much higher speeds on average than non-dimming associated events. They are also more likely to be associated with flares, and those flares tend to have the highest magnitudes. Thus dimmings give some measure of the available energy and magnetic configuration during an event. I will discuss in more detail what these results mean for understanding solar eruptions and what insight may be gained by further studies of these phenomena.