One-sided arc averaging geometries in time-distance local helioseismology

0548143 - ASÚ 2022 RIV FR eng J - Journal Article
Korda, D. - Švanda, Michal - Roudier, T.
One-sided arc averaging geometries in time-distance local helioseismology.
Astronomy & Astrophysics. Roč. 654, October (2021), č. článku A84. ISSN 0004-6361. E-ISSN 1432-0746
R&D Projects: GA ČR(CZ) GA18-06319S
Institutional support: RVO:67985815
Keywords : Sun * helioseismology * oscillations
OECD category: Astronomy (including astrophysics,space science)
Impact factor: 6.240, year: 2021
Method of publishing: Open access

We aim to create a new methodology to suppress the negative effects of magnetic fields on solar oscillations and measure plasma properties close to active regions. We constructed the one-sided arc averaging geometries and applied them to the non-linear approach of travel-time measurements. Using the one-sided arc travel times, we reconstructed the annulus travel times in a quiet-Sun region. We tested the methodology against the validated helioseismic inversion pipeline. We applied the new methodology for an inversion for surface horizontal flows in a region with a circular H-type sunspot. The inverted surface horizontal flows are comparable with the output of the coherent structure tracking, which is not strongly affected by the presence of the magnetic field. We show that the new methodology suppresses the negative effects of magnetic fields up to outer penumbra. We measure divergent flows with properties comparable to the moat flow. Conclusions. The new methodology can teach us about the depth structure of active regions and physical conditions that contribute to the evolution of the active regions.
Permanent Link: http://hdl.handle.net/11104/0324254