Chromospheric resonator model for sunspot revealed by multi-height observation of umbral wave

Fuente: arXiv
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Main Authors: Sangal, Kartika, Srivastava, A. K., Fu, Libo, Yuan, Ding, Feng, Song, Shen, Yuandeng
Format: Preprint
Published: 2026
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_version_ 1866914579557122048
author Sangal, Kartika
Srivastava, A. K.
Fu, Libo
Yuan, Ding
Feng, Song
Shen, Yuandeng
author_facet Sangal, Kartika
Srivastava, A. K.
Fu, Libo
Yuan, Ding
Feng, Song
Shen, Yuandeng
contents Sunspots are transient, magnetically intense features that host oscillations linked to magnetohydrodynamic (MHD) waves. These waves may contribute to plasma heating and drive mass flows in the solar wind. Beyond their energetic role, they serve as diagnostic tools for probing sunspot structure. In this study, we investigated chromospheric wave propagation in a sunspot using high-resolution, multi-wavelength observations from the Goode Solar Telescope at Big Bear Solar Observatory. Spectral analysis shows that the intensity at H$α$ line core and its wings exhibited oscillatory signal at about 3 min. We performed a cross-wavelet analysis to examine the phase relationship between the wing-integrated and line-core intensity oscillations of the H$α$ line and the centroid-derived H$α$ Doppler velocity. We also analyze the phase relationships between intensity pairs from different passband combinations of the H$α$ line. The results indicate the presence of slow magnetoacoustic modes manifesting standing waves along with upward propagating waves. The observed phase patterns suggest that umbral waves are confined within a non-ideal acoustic resonator, providing measurable wave properties that could serve as input for sunspot seismology and refine models of sunspot atmospheric structure.
format Preprint
id arxiv_https___arxiv_org_abs_2605_19472
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Chromospheric resonator model for sunspot revealed by multi-height observation of umbral wave
Sangal, Kartika
Srivastava, A. K.
Fu, Libo
Yuan, Ding
Feng, Song
Shen, Yuandeng
Solar and Stellar Astrophysics
Sunspots are transient, magnetically intense features that host oscillations linked to magnetohydrodynamic (MHD) waves. These waves may contribute to plasma heating and drive mass flows in the solar wind. Beyond their energetic role, they serve as diagnostic tools for probing sunspot structure. In this study, we investigated chromospheric wave propagation in a sunspot using high-resolution, multi-wavelength observations from the Goode Solar Telescope at Big Bear Solar Observatory. Spectral analysis shows that the intensity at H$α$ line core and its wings exhibited oscillatory signal at about 3 min. We performed a cross-wavelet analysis to examine the phase relationship between the wing-integrated and line-core intensity oscillations of the H$α$ line and the centroid-derived H$α$ Doppler velocity. We also analyze the phase relationships between intensity pairs from different passband combinations of the H$α$ line. The results indicate the presence of slow magnetoacoustic modes manifesting standing waves along with upward propagating waves. The observed phase patterns suggest that umbral waves are confined within a non-ideal acoustic resonator, providing measurable wave properties that could serve as input for sunspot seismology and refine models of sunspot atmospheric structure.
title Chromospheric resonator model for sunspot revealed by multi-height observation of umbral wave
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2605.19472