Transfer integrals for fully ionized gases

The general transfer integrals describing the collisional exchange of momentum and energy between the constituents of multicoimponent gases are evaluated for different plasma scenarios characterized by Maxwellian as well as non-Maxwellian distribution functions of the plasma species. Following a brief presentation of the standard approximation frequently employed in the literature, a comparison of numerical evaluations of the transfer integrals for various distribution functions reveals significant differences in the corresponding collisional momentum and energy exchange rates, which are shown to depend mainly on the core structure of the distributions. We demonstrate the inadequacy of the standard approximation and hence the importance of an accurate evaluation of the transfer integrals with an application to the electronproton as well as the heliumproton interaction in the solar wind plasma.