The Effects of Turbulent Electrical Resistivity on the Response of the Solar Atmosphere to Flare Energy Input. II. Hard X-Ray Spectra, Light Curves, and Spatial Distributions

Abstract In A. G. Emslie et al. (Paper I of this series), we examined the hydrodynamic response of the solar atmosphere to the injection of a beam of nonthermal electrons, with particular emphasis on the effects of turbulence on the electrical resistivity of the ambient plasma and so on the ohmic heating rate associated with driving the beam-neutralizing return current. In this work, we use the density and temperature profiles obtained in Paper I to determine the expected variation of X-ray intensity with position in the flare volume. Both nonthermal emission from direct-impact bremsstrahlung of the beam electrons and thermal emission from the hot plasma created by a combination of collisional and return-current ohmic heating are considered, and we also consider different orientations of the flare loop to the observational line of sight. We find that the presence of high levels of turbulence acts in general to attenuate the electron beam in the corona and so diminish the brightness of the direct-impact hard X-ray emission from the chromospheric footpoints, and also to create regions of very high-temperature emission in the corona, thus enhancing the thermal emission from the coronal part of the loop. The relative brightnesses of coronal and footpoint sources are examined for a variety of photon energies and turbulence parameters, and comparison with observations allows significant constraints to be placed on the properties of turbulence in flaring plasmas.