McKevitt, James;
Jarolim, Robert;
Matthews, Sarah;
Baker, Deborah;
Temmer, Manuela;
Veronig, Astrid;
Reid, Hamish;
(2024)
The Link between Nonthermal Velocity and Free Magnetic Energy in Solar Flares.
The Astrophysical Journal Letters
, 961
(2)
, Article L29. 10.3847/2041-8213/ad1bee.
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Abstract
The cause of excess spectral line broadening (nonthermal velocity) is not definitively known, but given its rise before and during flaring, the causal processes hold clues to understanding the triggers for the onset of reconnection and the release of free magnetic energy from the coronal magnetic field. A comparison of data during a 9 hr period from the extreme ultraviolet Imaging Spectrometer on the Hinode spacecraft—at a 3 minute cadence—and nonlinear force-free field extrapolations performed on Helioseismic and Magnetic Imager magnetograms—at a 12 minute cadence—shows an inverse relationship between nonthermal velocity and free magnetic energy on short timescales during two X-class solar flares on 2017 September 6. Analysis of these results supports suggestions that unresolved Doppler flows do not solely cause nonthermal broadening, and instead other mechanisms like Alfvén wave propagation and isotropic turbulence have a greater influence.
| Type: | Article |
|---|---|
| Title: | The Link between Nonthermal Velocity and Free Magnetic Energy in Solar Flares |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.3847/2041-8213/ad1bee |
| Publisher version: | https://doi.org/10.3847/2041-8213/ad1bee |
| Language: | English |
| Additional information: | Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. |
| 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 Space and Climate Physics |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10186252 |
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