ON THE COLLISIONAL ENERGY-TRANSFER BETWEEN THE CONSTITUENTS OF THE CORONAL PLASMA

It has been suggested that the distribution functions characterizing t he constituents of the solar coronal plasma are non-Maxwellian. If so, an accurate treatment of the collisional momentum and energy exchange between the plasma constituents within the framework of hydrodynamic models requires a re-evaluation of the general transfer integrals in m ulti-component plasmas. We have evaluated these integrals numerically for both Maxwellian and non-Maxwellian distribution functions of the p lasma species avoiding the standard approximation for the collision cr oss sections frequently employed in the literature. Significant differ ences are shown to exist in the energy exchange rates for different di stributions. We also demonstrate the inadequacy of the assumption of t hermodynamic equilibrium in the innermost solar wind and reveal the im portance of an accurate evaluation of the transfer integrals for the s olar coronal plasma based on more realistic velocity distributions.