What is heating the quiet-Sun chromosphere?

TL;DR

This paper challenges the prevailing view that acoustic wave dissipation heats the quiet-Sun chromosphere, presenting simulation evidence that acoustic flux may be sufficient for heating despite observational doubts.

Contribution

It demonstrates through 3D simulations and TRACE data comparison that acoustic flux can provide enough energy to heat the quiet-Sun chromosphere, countering recent observational claims.

Findings

Simulation shows sufficient acoustic flux for chromospheric heating.

Comparison with TRACE data supports the simulation results.

Discussion of magnetic fields and electric currents' roles.

Abstract

It is widely believed that the heating of the chromosphere in quiet-Sun internetwork regions is provided by dissipation of acoustic waves that are excited by the convective motions close to the top of the convection zone and in the photospheric overshoot layer. This view lately became challenged by observations suggesting that the acoustic energy flux into the chromosphere is too low, by a factor of at least ten. Based on a comparison of TRACE data with synthetic image sequences for a three-dimensional simulation extending from the top layers of the convection zone to the middle chromosphere, we come to the contradicting conclusion that the acoustic flux in the model provides sufficient energy for heating the solar chromosphere of internetwork regions. The role of a weak magnetic field and associated electric current sheets is also discussed.