Core to solar wind: a stepwise model for heating the solar corona

Abstract

Abstract The connection between nuclear fusion in the Sun’s core and solar irradiance, a central concern in climatology as well as astronomy, is obscured by uncertainty over the mechanism of coronal heating. Data from ground- and space-based instruments suggest that no single process is responsible and instead point to a cascade of mechanisms linking the solar interior with the solar wind. Electromagnetic energy derived from the Sun’s convection zone, and mediated by pseudo-Taylor column spin, gives rise to ohmic heating in the chromosphere raising its temperature to ~ 30,000 K. This triggers Joule-Thomson heating to 250,000 K in the transition region, whereupon plasma expansion in the near-vacuum of space takes over and brings the temperature to >1-2 million K. Besides accounting for the zonation of the solar atmosphere, the proposed sequence helps to explain how temperature increases stepwise away from the solar core and why the solar wind and photospheric sunspots share periodicities. Tokamak theory and practice complement astronomical modelling as the basis for an explanation. The scheme may apply to other solar stellar coronae.