Non-thermal Dupree diffusivity and shielding effects on atomic collisions in astrophysical turbulent plasmas

The influence of non-thermal Dupree turbulence and the plasma shielding on the electron-ion collision is investigated in astrophysical non-thermal Lorentzian turbulent plasmas. The second-order eikonal analysis and the effective interaction potential including the Lorentzian far-field term are employed to obtain the eikonal scattering phase shift and the eikonal collision cross section as functions of the diffusion coefficient, impact parameter, collision energy, Debye length and spectral index of the astrophysical Lorentzian plasma. It is shown that the non-thermal effect suppresses the eikonal scattering phase shift. However, it enhances the eikonal collision cross section in astrophysical non-thermal turbulent plasmas. The effect of non-thermal turbulence on the eikonal atomic collision cross section is weakened with increasing collision energy. The variation of the atomic cross section due to the non-thermal Dupree turbulence is also discussed. (C) 2015 Elsevier B.V. All rights reserved.This paper is dedicated to the late Prof. R.J. Gould in memory of exciting and stimulating collaborations on atomic processes in astrophysical plasmas. One of the authors (Y.-D.J.) gratefully acknowledges Prof. W. Roberge for useful discussions and warm hospitality while visiting the Department of Physics, Applied Physics, and Astronomy at Rensselaer Polytechnic Institute. This research was initiated while one of the authors (Y.-D.J.) was affiliated with Rensselaer as a visiting professor. This research was supported by National R&D Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (Grant no. 2015M1A7A1A01002786)