Reverse Current Dynamics in a Turbulent Flaring Atmosphere

It is becoming increasingly apparent that turbulence may play an important role in energy release and transport in solar flares. Recent work has studied the role that turbulence can play in (1) modifying the coefficient of thermal conductivity and hence the efficiency of energy transport by thermal conduction, and (2) determining the shape of optically thin diagnostic spectral line profiles that are excited in the ambient atmosphere. In this work we extend this approach to address the complementary issue of how turbulence affects the electrical conductivity and hence the strength of the electric field necessary to drive cospatial return currents. Using RADYN and Fokker-Planck codes in conjunction with thermal and electrical transport coefficients that self-consistently reflect an environment in which both collisional and turbulent transport occur, we model the collisional and Ohmic dynamics of electron beams injected during the impulsive phase of solar flares, the resulting hard X-ray spectral signature, the hydrodynamic response of the solar atmosphere, and the resulting profiles of key diagnostic spectral lines. We compare the results obtained with those obtained assuming purely collisional transport, and hence assess the ability of various diagnostics, such as hard X-ray spectra and EUV spectral line profiles, to infer empirically the role of turbulence in the flaring solar atmosphere.