Collisionless transport equations derived from a kinetic exospheric solar wind model with kappa velocity distribution functions

TL;DR

This paper derives collisionless transport equations from a kinetic exospheric solar wind model using kappa velocity distributions, validating the macroscopic equations with a kinetic approach for electrons and protons.

Contribution

It presents a rigorous derivation of macroscopic transport equations from a kinetic exospheric model with kappa distributions, including analysis of term importance.

Findings

Kinetic description with kappa distributions satisfies transport equations.

Model applied at 1.5 solar radii to 1 AU for different kappa indices.

Analysis of term contributions in macroscopic equations.

Abstract

In this paper we discuss the collisionless transport equations, continuity, momentum and energy conservation, derived from a kinetic exospheric model of the solar wind based on a kappa velocity distribution function of the electrons. The model is stationary and is based on a non-monotonic potential energy for the protons. The present study is carried out for an exobase located at 1.5 solar radii and for two different values of the kappa index. The maximum radial distance considered is equal to one astronomical unit. The moments of the velocity distribution function computed with the kinetic exospheric model for both electrons and protons are introduced into the mass continuity equation, momentum conservation equation and energy conservation equation. The relative importance of various terms in the macroscopic transport equations for each component species are analyzed and discussed. The results obtained show that the kinetic description based on kappa velocity distribution functions satisfies rigorously the transport equations that give a macroscopic description of the solar wind plasma.