French, RJ;
Judge, PG;
Matthews, SA;
Driel-Gesztelyi, LV;
(2019)
Spectropolarimetric Insight into Plasma Sheet Dynamics of a Solar Flare.
The Astrophysical Journal Letters
, 887
(2)
, Article L34. 10.3847/2041-8213/ab5d34.
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Abstract
We examine spectropolarimetric data from the Coronal Multi-channel Polarimeter (CoMP) instrument, acquired during the evolution of the 2017 September 10 X8.2 solar flare on the western solar limb. CoMP captured linearly polarized light from two emission lines of Fe xiii at 1074.7 and 1079.8 nm, from 1.03 to 1.5 solar radii. We focus here on the hot plasma sheet lying above the bright flare loops and beneath the ejected coronal mass ejection. The polarization has a striking and coherent spatial structure, with unexpectedly small polarization aligned with the plasma sheet. By elimination, we find that small-scale magnetic field structure is needed to cause such significant depolarization, and suggest that plasmoid formation during reconnection (associated with the tearing-mode instability) creates magnetic structure on scales below instrument resolution of 6 Mm. We conclude that polarization measurements with new coronagraphs, such as the upcoming Daniel K. Inouye Solar Telescope, will further enhance our understanding of magnetic reconnection and development of turbulence in the solar corona.
| Type: | Article |
|---|---|
| Title: | Spectropolarimetric Insight into Plasma Sheet Dynamics of a Solar Flare |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.3847/2041-8213/ab5d34 |
| Publisher version: | https://doi.org/10.3847/2041-8213/ab5d34 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Solar magnetic reconnection (1504); Solar flares (1496); Spectropolarimetry (1973); Solar magnetic fields (1503) |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10088743 |
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