Directivity and polarization dynamics of hard X-ray and gamma-ray emission of a flare loop

The peculiarities of the directivity and polarization dynamics of hard X-rays and gamma-rays from different regions of a flare loop were studied based on numerical modeling of the distribution dynamics of energetic electrons in the loop upon their nonstationary but fairly long-lasting injection at the top of the magnetic loop. The modeling results suggest that the degree of directivity and polarization and the variation of these parameters in time depend on the position within the loop and vary fundamentally between cases of isotropic and anisotropic (longitudinal) injection of electrons. The revealed peculiarities of the directivity and polarization dynamics may be used in X-ray and gamma-ray diagnostics of the type of pitch-angle distribution that characterizes the electrons accelerated in a certain specific observed flare.