eprintid: 10186252 rev_number: 12 eprint_status: archive userid: 699 dir: disk0/10/18/62/52 datestamp: 2024-01-30 11:54:53 lastmod: 2024-01-30 11:54:53 status_changed: 2024-01-30 11:54:53 type: article metadata_visibility: show sword_depositor: 699 creators_name: McKevitt, James creators_name: Jarolim, Robert creators_name: Matthews, Sarah creators_name: Baker, Deborah creators_name: Temmer, Manuela creators_name: Veronig, Astrid creators_name: Reid, Hamish creators_name: Green, Lucie title: The Link between Nonthermal Velocity and Free Magnetic Energy in Solar Flares ispublished: pub divisions: UCL divisions: B04 divisions: C06 divisions: F63 note: 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. 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. date: 2024-02-01 date_type: published publisher: American Astronomical Society official_url: https://doi.org/10.3847/2041-8213/ad1bee oa_status: green full_text_type: pub language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 2142306 doi: 10.3847/2041-8213/ad1bee lyricists_name: Matthews, Sarah lyricists_name: Green, Lucinda lyricists_name: McKevitt, James lyricists_name: Baker, Deborah lyricists_name: Reid, Hamish lyricists_id: SAMAT57 lyricists_id: LGREE15 lyricists_id: JEMCK82 lyricists_id: DBAKE94 lyricists_id: HASRE98 actors_name: Kalinowski, Damian actors_id: DKALI47 actors_role: owner full_text_status: public publication: The Astrophysical Journal Letters volume: 961 number: 2 article_number: L29 issn: 2041-8205 citation: McKevitt, James; Jarolim, Robert; Matthews, Sarah; Baker, Deborah; Temmer, Manuela; Veronig, Astrid; Reid, Hamish; McKevitt, James; Jarolim, Robert; Matthews, Sarah; Baker, Deborah; Temmer, Manuela; Veronig, Astrid; Reid, Hamish; Green, Lucie; - view fewer <#> (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 <https://doi.org/10.3847/2041-8213%2Fad1bee>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10186252/2/McKevitt_2024_ApJL_961_L29.pdf