Enhanced Three-minute Oscillation above a Sunspot during a Solar Flare
Enhanced Three-minute Oscillation above a Sunspot during a Solar Flare
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DOI：
10.3847/1538-4357/ad10a9
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发表时间：
2023-11
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影响因子：
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通讯作者：
Ya Wang;Lyndsay Fletcher;Sargam M. Mulay;Haisheng Ji;Wenda Cao
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作者：
Ya Wang;Lyndsay Fletcher;Sargam M. Mulay;Haisheng Ji;Wenda Cao
在太阳黑子上方的色球层中，三分钟振荡是一种常见的现象。振荡可能受到与太阳耀斑有关的能量释放过程的影响。在本文中，我们报告了耀斑事件SOL 2012 -07- 05 T21：42中的增强振荡，其周期约为3分钟，发生在太阳黑子本影-半影边界的耀斑带位置，并在色球和日冕通带中观察到。利用大熊太阳观测站古德太阳望远镜的地面观测和太阳动力学观测站的空间观测同时对这种振荡进行了分析。在耀斑之前和之后观察到频率偏移，在耀斑之前以大约200 s的周期存在的运行半影波与耀斑之后在相同位置以180 s的周期存在的加强振荡共存。我们还发现了不同的通带之间的相位差，与振荡发生从高温到低温通带。理论上，频率的变化强烈地依赖于磁场倾角和色球温度的变化。在分析该地区的特性后，我们发现频率变化是由磁倾斜角相对于当地垂直方向的略微减小引起的。此外，我们认为，增强的3分钟振荡与额外的加热，可能是由于下降流，在EUV后期的耀斑。
Three-minute oscillations are a common phenomenon in the solar chromosphere above a sunspot. Oscillations can be affected by the energy release process related to solar flares. In this paper, we report on an enhanced oscillation in flare event SOL2012-07-05T21:42 with a period of around 3 minutes that occurred at the location of a flare ribbon at a sunspot umbral–penumbral boundary and was observed in both chromospheric and coronal passbands. An analysis of this oscillation was carried out using simultaneous ground-based observations from the Goode Solar Telescope at the Big Bear Solar Observatory and space-based observations from the Solar Dynamics Observatory. A frequency shift was observed before and after the flare, with the running penumbral wave that was present with a period of about 200 s before the flare coexisting with a strengthened oscillation with a period of 180 s at the same locations after the flare. We also found a phase difference between different passbands, with the oscillation occurring from high-temperature to low-temperature passbands. Theoretically, the change in frequency was strongly dependent on the variation of the inclination of the magnetic field and the chromospheric temperature. Following an analysis of the properties of the region, we found the frequency change was caused by a slight decrease of the magnetic inclination angle with respect to the local vertical. In addition, we suggest that the enhanced 3 minute oscillation was related to the additional heating, maybe due to the downflow, during the EUV late phase of the flare.