Observations of ubiquitous compressive waves in the Sun's chromosphere

TL;DR

This paper reports the first on-disk observations of both compressible and incompressible MHD waves in the Sun's chromosphere, highlighting their potential role in solar atmospheric heating.

Contribution

It provides new observational evidence of concurrent MHD wave modes on the solar disk, including estimates of their energy flux and implications for coronal heating mechanisms.

Findings

Ubiquitous presence of MHD waves in the chromosphere

Estimated wave energy flux sufficient for heating

Upper bound on wave energy reaching the corona

Abstract

The details of the mechanism(s) responsible for the observed heating and dynamics of the solar atmosphere still remain a mystery. Magnetohydrodynamic (MHD) waves are thought to play a vital role in this process. Although it has been shown that incompressible waves are ubiquitous in off-limb solar atmospheric observations their energy cannot be readily dissipated. We provide here, for the first time, on-disk observation and identification of concurrent MHD wave modes, both compressible and incompressible, in the solar chromosphere. The observed ubiquity and estimated energy flux associated with the detected MHD waves suggest the chromosphere is a vast reservoir of wave energy with the potential to meet chromospheric and coronal heating requirements. We are also able to propose an upper bound on the flux of the observed wave energy that is able to reach the corona based on observational constraints, which has important implications for the suggested mechanism(s) for quiescent coronal heating.