Origin of the Chromospheric Umbral Waves in Sunspots

Fuente: arXiv
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Hauptverfasser: Zhang, Xinsheng, Yan, Xiaoli, Xue, Zhike, Wang, Jincheng, Xu, Zhe, Li, Qiaoling, Peng, Yang, Yang, Liping
Format: Preprint
Veröffentlicht: 2024
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author Zhang, Xinsheng
Yan, Xiaoli
Xue, Zhike
Wang, Jincheng
Xu, Zhe
Li, Qiaoling
Peng, Yang
Yang, Liping
author_facet Zhang, Xinsheng
Yan, Xiaoli
Xue, Zhike
Wang, Jincheng
Xu, Zhe
Li, Qiaoling
Peng, Yang
Yang, Liping
contents Oscillations are ubiquitous in sunspots and the associated higher atmospheres. However, it is still unclear whether these oscillations are driven by the external acoustic waves (p-modes) or generated by the internal magnetoconvection. To obtain clues about the driving source of umbral waves in sunspots, we analyzed the spiral wave patterns (SWPs) in two sunspots registered by IRIS MgII 2796 Å slit-jaw images. By tracking the motion of the SWPs, we find for the first time that two one-armed SWPs coexist in the umbra, and they can rotate either in the same or opposite directions. Furthermore, by analyzing the spatial distribution of the oscillation centers of the one-armed SWPs within the umbra (the oscillation center is defined as the location where the SWP first appears), we find that the chromospheric umbral waves repeatedly originate from the regions with high oscillation power and most of the umbral waves occur in the dark nuclei and strong magnetic field regions of the umbra. Our study results indicate that the chromospheric umbral waves are likely excited by the p-mode oscillations.
format Preprint
id arxiv_https___arxiv_org_abs_2407_01941
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Origin of the Chromospheric Umbral Waves in Sunspots
Zhang, Xinsheng
Yan, Xiaoli
Xue, Zhike
Wang, Jincheng
Xu, Zhe
Li, Qiaoling
Peng, Yang
Yang, Liping
Solar and Stellar Astrophysics
Oscillations are ubiquitous in sunspots and the associated higher atmospheres. However, it is still unclear whether these oscillations are driven by the external acoustic waves (p-modes) or generated by the internal magnetoconvection. To obtain clues about the driving source of umbral waves in sunspots, we analyzed the spiral wave patterns (SWPs) in two sunspots registered by IRIS MgII 2796 Å slit-jaw images. By tracking the motion of the SWPs, we find for the first time that two one-armed SWPs coexist in the umbra, and they can rotate either in the same or opposite directions. Furthermore, by analyzing the spatial distribution of the oscillation centers of the one-armed SWPs within the umbra (the oscillation center is defined as the location where the SWP first appears), we find that the chromospheric umbral waves repeatedly originate from the regions with high oscillation power and most of the umbral waves occur in the dark nuclei and strong magnetic field regions of the umbra. Our study results indicate that the chromospheric umbral waves are likely excited by the p-mode oscillations.
title Origin of the Chromospheric Umbral Waves in Sunspots
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2407.01941