Alfv\'enic Wave Heating of the Upper Chromosphere in Flares

TL;DR

This paper presents a numerical model demonstrating that Alfvénic waves can effectively heat the upper chromosphere during solar flares, leading to phenomena like chromospheric evaporation, with implications for understanding flare energy transport.

Contribution

The study introduces a new numerical model analyzing how Alfvénic waves dissipate and heat the chromosphere, highlighting their role in flare dynamics and comparison to electron beam heating.

Findings

Alfvénic waves can significantly heat the upper chromosphere during flares.

Wave dissipation leads to explosive chromospheric evaporation.

Heating effects are similar to those caused by electron beams.

Abstract

We have developed a numerical model of flare heating due to the dissipation of Alfv\'enic waves propagating from the corona to the chromosphere. With this model, we present an investigation of the key parameters of these waves on the energy transport, heating, and subsequent dynamics. For sufficiently high frequencies and perpendicular wave numbers, the waves dissipate significantly in the upper chromosphere, strongly heating it to flare temperatures. This heating can then drive strong chromospheric evaporation, bringing hot and dense plasma to the corona. We therefore find three important conclusions: (1) Alfv\'enic waves, propagating from the corona to the chromosphere, are capable of heating the upper chromosphere and the corona, (2) the atmospheric response to heating due to the dissipation of Alfv\'enic waves can be strikingly similar to heating by an electron beam, and (3) this heating can produce explosive evaporation.