Collisional cross sections and momentum distributions in astrophysical plasmas: dynamics and statistical mechanics link

Abstract

We show that, in stellar core plasmas, the one-body momentum distribution function is strongly dependent, at least in the high velocity regime, on the microscopic dynamics of ion elastic collisions and therefore on the effective collisional cross sections, if a random force field is present. We take into account two cross sections describing ion-dipole and ion-ion screened interactions. Furthermore we introduce a third unusual cross section, to link statistical distributions and a quantum effect originated by the energy-momentum uncertainty owing to many-body collisions, and propose a possible physical interpretation in terms of a tidal-like force. We show that each collisional cross section gives rise to a slight peculiar correction on the Maxwellian momentum distribution function in a well defined velocity interval. We also find a possible link between microscopical dynamics of ions and statistical mechanics interpreting our results in the framework of non-extensive statistical mechanics.

8 pages

References in corpus (3)

• Dynamical scenario for nonextensive statistical mechanics
• Non-extensive resonant reaction rates in astrophysical plasmas
• News and expectations in Thermostatistics

Cited by in corpus (4)

• Modified Debye-Huckel Electron Shielding and Penetration Factor
• Analytical predictions of non-Gaussian distribution parameters for stellar plasmas
• The role of correlation entropy in nuclear fusion in liquid lithium, indium and mercury
• Nonextensive Interpretation Of Radiative Recombination In Electron Cooling