Energy Release During Several M and X Class Flares

The mechanisms of energy release, energy transfer, mass motions, and electrons acceleration during a flare has not been understood very well. We analyzed several flares by using SDO observations combined with IRIS spectral and slit-jaw images to study their properties. In most of these flares, there are obvious redshift and blueshift patterns. We also discussed the evolutions of mass motions related to chromospheres condensations and evaporations.