Observation of 2011-02-15 X2.2 Flare in Hard X-Ray and Microwave

Abstract:

Previous studies have shown that the energy release mechanism of some solar flares follow the Standard magnetic-reconnection model, but the detailed properties of high-energy electrons produced in the flare are still not well understood. We conducted a unique, multi-wavelength study that discloses the spatial, temporal and energy distributions of the accelerated electrons in the X2.2 solar flare on Feb. 15, 2011.

We studied the source locations of the observed seven temporal peaks in hard X-ray (HXR) and microwave (MW) lightcurves using the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) in 50-75 keV channels and Nobeyama Radioheliograph (NoRH) in 34 GHz, respectively. We found that peak emissions were coming from two spatially distinct sites in HXR and MW, and in HXR we observed a sudden change between these sites over the second and the third peak. Comparison between the HXR lightcurve and the temporal variations in MW source kernel intensity also confirmed that seven peak emissions were actually coming from two sources, each with their own multiple peaks.