Evidence for the photospheric excitation of incompressible chromospheric waves

TL;DR

This study provides observational evidence linking photospheric vortex motions to the excitation of incompressible transverse waves in the chromosphere, enhancing understanding of energy transfer in the solar atmosphere.

Contribution

It demonstrates the connection between photospheric vortex motions and chromospheric transverse waves using new observational techniques and comparisons with simulations.

Findings

Incompressible waves are excited by photospheric vortex motions.

Chromospheric torsional motions are observed as counterparts to photospheric vortices.

Transverse wave properties are measured from time-distance diagrams.

Abstract

Observing the excitation mechanisms of incompressible transverse waves is vital for determining how energy propagates through the lower solar atmosphere. We aim to show the connection between convectively driven photospheric flows and incompressible chromospheric waves. The observations presented here show the propagation of incompressible motion through the quiet lower solar atmosphere, from the photosphere to the chromosphere. We determine photospheric flow vectors to search for signatures of vortex motion and compare results to {photospheric flows present in} convective simulations. Further, we search for the chromospheric response to vortex motions. Evidence is presented that suggests incompressible waves can be excited by the vortex motions of a strong magnetic flux concentration in the photosphere. A chromospheric counterpart to the photospheric vortex motion is also observed, presenting itself as a quasi-periodic torsional motion. Fine-scale, fibril structures that emanate from the chromospheric counterpart support transverse waves that are driven by the observed torsional motion. A new technique for obtaining details of transverse waves from time-distance diagrams is presented and the properties of transverse waves (e.g., amplitudes and periods) excited by the chromospheric torsional motion are measured.