Spectroscopic Observations of an Evolving Flare Ribbon Substructure Suggesting Origin in Current Sheet Waves

Brannon, S. R., D. W. Longcope, and J. Qiu, Spectroscopic Observations of an Evolving Flare Ribbon Substructure Suggesting Origin in Current Sheet Waves, ApJ, 810, 4 (2015) (ADS)

The cartoon

(click on the image for a larger version)

Trying to explain some unique signatures of flows inferred from EUV observations. Unique, but perhaps other cases will appear: the evaporation flows appear to *gyrate as they expand along flux tubes embedded in the flare ribbons. This is attributed to MHD instabilities in the current sheet (upper panel), possibly Kelvin-Helmholtz or tearing mode; these produce large-scale displacements that propagate down to the flare ribbons. The Archivist speculates that Poynting flux might be involved here.

Date: 2020 April 21