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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Objective Lagrangian Vortex Detection in the Solar Photosphere

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de Souza e Almeida Silva, Suzana [1] ; Rempel, Erico Luiz [1, 2] ; Pinheiro Gomes, Tiago Francisco [1, 2] ; Requerey, Iker S. [3] ; Chian, Abrahamm C. -L. [4, 2]
Total Authors: 5
[1] Inst Tecnol Aeronaut, Praca Marechal Eduardo Gomes, 50 Vila Acacias, BR-12228900 Sao Jose Dos Campos, SP - Brazil
[2] Natl Inst Space Res INPE, Av Astronautas 1-758, BR-12227010 Sao Jose Dos Campos, SP - Brazil
[3] Max Planck Inst Solar Syst Res, Justus Von Liebig Weg 3, D-37077 Gottingen - Germany
[4] Univ Adelaide, Sch Math Sci, Adelaide, SA 5005 - Australia
Total Affiliations: 4
Document type: Journal article
Source: Astrophysical Journal Letters; v. 863, n. 1 AUG 10 2018.
Web of Science Citations: 2

Vortices in the solar photosphere can be linked to a wide range of events, such as small-scale solar eruptions, wave excitation, and heating of the upper part of the solar atmosphere. Despite their importance in solar physics, most of the current studies on photospheric vortices are based on methods that are not invariant under time-dependent translations and rotations of the reference frame and are Eulerian; i.e., they are based on single snapshots of a velocity field and, therefore, do not convey information on the true long-term motion of fluid particles on a time-varying field. Another issue with methods for vortex detection is that typically they provide false identifications in highly compressible flows. This Letter presents a novel criterion that effectively removes wrong detections based on the geometry of the streamlines of the displacement vector of fluid elements and can be readily applied to other astrophysical flows. The new criterion is applied to the Lagrangian-averaged vorticity deviation (LAVD), which is a recently developed frame invariant vortex detection method. The advantage of LAVD is that it delimits the vortices' outer boundaries precisely by following up the trajectories of fluid elements in space and time. The proposed method is compared with two other techniques using horizontal velocity fields extracted from Hinode satellite data. (AU)

FAPESP's process: 13/26258-4 - Superdense matter in the universe
Grantee:Manuel Máximo Bastos Malheiro de Oliveira
Support type: Research Projects - Thematic Grants