The Link between Nonthermal Velocity and Free Magnetic Energy in Solar Flares
- Autor(en)
- James McKevitt, Robert Jarolim, Sarah Matthews, Deborah Baker, Manuela Temmer, Astrid Veronig, Hamish Reid, Lucie Green
- Abstrakt
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.
- Organisation(en)
- Institut für Astrophysik
- Externe Organisation(en)
- University College London, Karl-Franzens-Universität Graz
- Journal
- Astrophysical Journal Letters
- Band
- 961
- Anzahl der Seiten
- 7
- ISSN
- 2041-8205
- DOI
- https://doi.org/10.3847/2041-8213/ad1bee
- Publikationsdatum
- 02-2024
- Peer-reviewed
- Ja
- ÖFOS 2012
- 103003 Astronomie, 103004 Astrophysik
- ASJC Scopus Sachgebiete
- Astronomy and Astrophysics, Space and Planetary Science
- Link zum Portal
- https://ucrisportal.univie.ac.at/de/publications/714bc0a4-f3f2-4c16-ac5e-2e1e5a8f0d30