On the Exospheric Approach for the Solar Wind Acceleration

Abstract

We present the basics of the exospheric models of the solar wind acceleration. In these models the plasma is assumed fully collisionless above a typical altitude in the corona. The solar wind is accelerated by the interplanetary electrostatic potential which is needed to warrant the equality of the proton and electron fluxes. These models suggest that the fast wind emanating from the polar regions could be due to the presence of non-thermal electron distributions in the corona.