Magnetoacoustic Shocks and Spectropolarimetric Signals in He I 10830 Å

Fuente: arXiv
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Main Authors: Kumar, Hirdesh, Felipe, Tobias, Kuckein, Christoph, Manrique, S. J. González, Ramos, A. Asensio
Format: Preprint
Published: 2026
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_version_ 1866908882139348992
author Kumar, Hirdesh
Felipe, Tobias
Kuckein, Christoph
Manrique, S. J. González
Ramos, A. Asensio
author_facet Kumar, Hirdesh
Felipe, Tobias
Kuckein, Christoph
Manrique, S. J. González
Ramos, A. Asensio
contents Umbral flashes are manifestations of magnetoacoustic shocks in the solar chromosphere. These phenomena are thought to influence the evolution of chromospheric umbral magnetic fields. However, the impact of these shocks on inferred chromospheric magnetic field oscillations remains unclear. We examined five different sunspots located near the solar disk center, observed with the GRIS instrument installed at the GREGOR telescope. The HAZEL2 Spectropolarimetric inversion code is used to obtain the photospheric and chromospheric line-of-sight velocities and magnetic fields in Si 10827 Å and He 10830 Å spectral lines, respectively, using various inversion strategies. In the inversions with one chromospheric component, three of the sunspots exhibit remarkably stronger magnetic fields accompanying the shocks, while the other two sunspots show striking reductions in the magnetic field. Alternatively, the Stokes profiles can be reproduced by models with two chromospheric slabs, one on top of the other, through two-component inversions. These inversions provide excellent fits even when magnetic field fluctuations are discarded by imposing a constant magnetic field during the whole temporal series. In this scenario, the observed Stokes profiles are interpreted as the result of strong velocity gradients, where the He 10830 Å line is sensitive to both sides of the shock front. Both competing models explaining the spectral profiles during the shocks, either large magnetic field fluctuations or velocity gradients, are critically discussed.
format Preprint
id arxiv_https___arxiv_org_abs_2603_12213
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Magnetoacoustic Shocks and Spectropolarimetric Signals in He I 10830 Å
Kumar, Hirdesh
Felipe, Tobias
Kuckein, Christoph
Manrique, S. J. González
Ramos, A. Asensio
Solar and Stellar Astrophysics
Umbral flashes are manifestations of magnetoacoustic shocks in the solar chromosphere. These phenomena are thought to influence the evolution of chromospheric umbral magnetic fields. However, the impact of these shocks on inferred chromospheric magnetic field oscillations remains unclear. We examined five different sunspots located near the solar disk center, observed with the GRIS instrument installed at the GREGOR telescope. The HAZEL2 Spectropolarimetric inversion code is used to obtain the photospheric and chromospheric line-of-sight velocities and magnetic fields in Si 10827 Å and He 10830 Å spectral lines, respectively, using various inversion strategies. In the inversions with one chromospheric component, three of the sunspots exhibit remarkably stronger magnetic fields accompanying the shocks, while the other two sunspots show striking reductions in the magnetic field. Alternatively, the Stokes profiles can be reproduced by models with two chromospheric slabs, one on top of the other, through two-component inversions. These inversions provide excellent fits even when magnetic field fluctuations are discarded by imposing a constant magnetic field during the whole temporal series. In this scenario, the observed Stokes profiles are interpreted as the result of strong velocity gradients, where the He 10830 Å line is sensitive to both sides of the shock front. Both competing models explaining the spectral profiles during the shocks, either large magnetic field fluctuations or velocity gradients, are critically discussed.
title Magnetoacoustic Shocks and Spectropolarimetric Signals in He I 10830 Å
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2603.12213