Solar wind speed theory and the nonextensivity of solar corona

TL;DR

This paper extends solar wind speed theory by incorporating nonextensive statistical mechanics to account for the complex, nonisothermal, and self-gravitating nature of the solar corona, revealing a deceleration effect on solar wind speed.

Contribution

It introduces a nonextensive framework to generalize solar wind speed theory, considering the corona's non-equilibrium and nonextensive properties for the first time.

Findings

Nonextensivity reduces gas pressure outward in the corona.

The nonextensive model predicts a significant deceleration of solar wind speed.

The approach links corona's thermodynamic properties with solar wind dynamics.

Abstract

The solar corona is a complex system, with nonisothermal plasma and being in the self-gravitating field of the Sun. So the corona plasma is not only a nonequilibrium system but also a nonextensive one. We estimate the parameter of describing the degree of nonextensivity of the corona plasma and study the generalization of the solar wind speed theory in the framework of nonextensive statistical mechanics. It is found that, when use Chapman's corona model (1957) as the radial distribution of the temperature in the corona, the nonextensivity reduces the gas pressure outward and thus leads a significant deceleration effect on the radial speed of the solar wind.