Vertical and horizontal heating in solar chromosphere

Abstract

Anisotropy of the stress tensor of turbulent waves is used in this paper to explain the effects of Alfven waves in a magnetic tube. Under the conditions of a force-free field with negligible thermal conduction and convection, the equations governing the behaviour of a one-dimensional steady flow are derived. The calculated results give a reasonable explanation of the observations that the density in a plage is of the same order as, and slightly higher than the density in the surroundings while the temperature is higher by a few hundred degrees. The model of horizontal heating explains the temperature excess in “plage bridges”. The fact that, in the quiet regions, bright patches are often where the vertical field is strong while dark filaments correspond to locations with predominent horizontal field can be attributed to the different amounts of absorption of the turbulent waves by magnetic field of different strengths.