The well-established notion of a “ common population ” of the accelerated electrons simultaneously producing the hard X-ray ( HXR ) and the microwave ( MW ) emission during the flare impulsive phase has been challenged by some studies reporting the discrepancies between the HXR-inferred and the MW-inferred electron energy spectra .
The traditional methods of their spectral inversion have some problems that can be mainly attributed to the unrealistic and the oversimplified treatment of the flare emission .
To properly address this problem , we use a Non-linear Force Free Field ( NLFFF ) model extrapolated from an observed photospheric magnetogram as input to the three-dimensional , multi-wavelength modeling platform GX Simulator , and create a unified electron population model that can simultaneously reproduce the observed HXR and MW observations .
We model the end of the impulsive phase of the 2015-06-22 M6.5 flare , and constrain the modeled electron spatial and energy parameters using observations made by the highest-resolving instruments currently available in two wavelengths , the Reuven Ramaty High Energy Solar Spectroscopic Imager ( RHESSI ) for HXR and the Expanded Owens Valley Solar Array ( EOVSA ) for MW .
Our results suggest that the HXR-emitting electron population model fits the standard flare model with a broken power-law spectrum ( { E _ { break } } \sim 200 keV ) that simultaneously produces the HXR footpoint emission and the MW high frequency emission .
The model also includes an “ HXR invisible ” population of nonthermal electrons that are trapped in a large volume of magnetic field above the HXR-emitting loops , which is observable by its gyrosynchrotron ( GS ) radiation emitting mainly in MW low frequency range .