Institution(s): 1. New Jersey Institute of Technology
Uninterrupted observations from Solar Dynamics Observatory provide unique opportunity for investigation of "sunquakes", helioseismic waves caused by strong localized impacts in the low atmosphere during impulsive phase of solar flares. The SDO observations show that these events are more frequent than previously thought. They are observed in solar flares from C- to X-classes. However, not all X-class flares produce sunquakes, and it is puzzling why some relatively weak flares produce sunquakes, while significantly more powerful flares do not. Using data from the Helioseismic and Magnetic Imager (HMI) and Atmospheric Imaging Assembly (AIA) I investigate properties of sunquakes by detecting and analyzing the seismic wave fronts and the sources of the flare impact, and discuss physical mechanisms of the impact. By comparing energetic and morphological characteristics of the flares with and without sunquakes, I present arguments that this phenomenon reflects a division between two classes of solar flares: confined and eruptive, which may be fundamentally different in terms of the energy release mechanism.