La méthode de Grad des 20 moments et les invariants CGL. Application au vent solaire

Abstract

The experimental data of the quiet solar wind appear to be the result of perturbations over the simple expansion of the solar plasma. The distribution function obtained by the 20 moments Grad method, but simplified by the parallel flux has been proposed by Whang to interpret the experimental data of Hundhausen. This distribution has been used to close the moments system of a simple expansion which gives the perpendicular and parallel contribution to the parallel heat flux. The terms in the development which immediately follow the CGL invariants are obtained. The numerical value of the heat flux agrees with Whang's and Hundhausen's, and the corrections to the invariants are in agreement with the kinetic results of Hollweg and HD of Fridman if the closure of the moments system is made by the highly supersonic flux condition.