The drivers of active region outflows into the slow solar wind
Abstract
Plasma outflows from the edges of active regions have been suggested as a possible source of the slow solar wind. Spectroscopic measurements show that these outflows have an enhanced elemental composition, which is a distinct signature of the slow wind. Current spectroscopic observations, however, do not have sufficient spatial resolution to distinguish what structures are being measured or to determine the driver of the outflows. The High-resolution Coronal Imager (Hi-C) flew on a sounding rocket in May, 2018, and observed areas of active region outflow at the highest spatial resolution ever achieved (250 km). Here we use the Hi-C data to disentangle the outflow composition signatures observed with the Hinode satellite during the flight. We show that there are two components to the outflow emission: a substantial contribution from expanded plasma that appears to have been expelled from closed loops in the active region core, and a second contribution from dynamic activity in active region plage, with a composition signature that reflects solar photospheric abundances. The two competing drivers of the outflows may explain the variable composition of the slow solar wind.
Keywords
Cite
@article{arxiv.2004.07461,
title = {The drivers of active region outflows into the slow solar wind},
author = {David H. Brooks and Amy R. Winebarger and Sabrina Savage and Harry P. Warren and Bart De Pontieu and Hardi Peter and Jonathan W. Cirtain and Leon Golub and Ken Kobayashi and Scott W. McIntosh and David McKenzie and Richard Morton and Laurel Rachmeler and Paola Testa and Sanjiv Tiwari and Robert Walsh},
journal= {arXiv preprint arXiv:2004.07461},
year = {2020}
}
Comments
To be published in The Astrophysical Journal. Figures 1, 2, 3 and 12 are reduced resolution to meet size requirements. The original figures will appear in the published version