Anisotropic turbulent model for solar coronal heating

TL;DR

This paper develops a self-consistent anisotropic turbulent model for solar coronal heating, incorporating wave MHD turbulence effects to accurately predict heating rates and turbulent velocities in various solar regions.

Contribution

It introduces a novel anisotropic turbulence model that includes magnetic field effects, improving the understanding of coronal heating mechanisms.

Findings

Heating rate matches observations in quiet and active regions.

Turbulent velocity predictions align with empirical data.

Model works for both magnetic loops and open field lines.

Abstract

Context : We present a self-consistent model of solar coronal heating, originally developed by Heyvaert & Priest (1992), in which we include the dynamical effect of the background magnetic field along a coronal structure by using exact results from wave MHD turbulence (Galtier et al. 2000). Aims : We evaluate the heating rate and the microturbulent velocity for comparison with observations in the quiet corona, active regions and also coronal holes. Methods :The coronal structures are assumed to be in a turbulent state maintained by the slow erratic motions of the magnetic footpoints. A description for the large-scale and the unresolved small-scale dynamics are given separately. From the latter, we compute exactly (or numerically for coronal holes) turbulent viscosites that are finally used in the former to close self-consistently the system and derive the heating flux expression. Results : We show that the heating rate and the turbulent velocity compare favorably with coronal observations. Conclusions : Although the Alfven wave turbulence regime is strongly anisotropic, and could reduce a priori the heating efficiency, it provides an unexpected satisfactory model of coronal heating for both magnetic loops and open magnetic field lines.