Dynamics and Heating of Chromospheres

Abstract

Heating and dynamics of the solar as well as stellar chromospheres are separate phenomena, judging by their spatial and temporal characteristics in the Sun. Simulations of chromospheric heating in late-type stars as well as simulations of the dynamics of the large-amplitude oscillations of internetwork calcium bright points in the solar atmosphere reproduce the main features of the respective phenomena. Differences between models and observations imply (1) that the Sun has a permanent, hot chromosphere and that its temperature structure cannot be obtained by averaging the time-dependent temperature profile of a model that describes only the oscillations, and (2) that the acoustic waves causing the dynamics and the heating propagate upward as spherical waves.