Physics and Astronomy Dept., University of Glasgow, Glasgow G12 8QQ

Electron beam distribution functions found from a joint solution the kinetic and electric current conservation equations for electron beams scattered anisotropically in converging magnetic field and the induced electric field of return current are used for calculation of resulting fluxes of hard X-ray bremsstrahlung emission for beams with different parameters. The X-ray fluxes are shown to have non-monotonic energy distributions with a flux depression (dip) at 20-25 keV with the following maximum at 30-35 keV; spectral indices before the dips are higher than after by 1-1.5 units. This dip is associated with the return current effect at the transition region and upper chromosphere. This gives an opportunity to measure, from these two distributions and from energy at which the dip occurs, a magnitude of electric field of the return current. It will allow to refine our understanding of energy transfer by electron beams from the corona into deeper layers of a flaring atmosphere.