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arXiv 2209.07993astro-ph.SR
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用Si IV谱线研究IRIS观测的宁静太阳过渡区振荡

Spectroscopic study of solar transition region oscillations in the quiet-Sun observed by IRIS using Si IV spectral line

Kartika Sangal, A. K. Srivastava, P. Kayshap, T. J Wang, J. J. González-Avilés, Abhinav Prasad

摘要:

本文利用界面区成像光谱仪(IRIS)在宁静太阳上观测到的Si IV 1393.755谱线,确定了太阳过渡区振荡的物理本质。我们使用小波工具(例如,功率、交叉功率、相干性和相位差)以及严格的噪声模型(即,幂律+常数)。我们估计的强度和多普勒速度振荡在每个选定的位置在安静的太阳(QS)的周期和量化的统计显着的功率和相关的周期在一个明亮的和两个黑暗的区域的分布。在亮TR区,强度和速度的平均周期分别为7 min和8 min。在暗区,强度和速度的平均周期分别为7分钟和5.4分钟。我们还估计在每个位置的强度和多普勒速度振荡之间的相位差。估计相位差的统计分布,其峰值在-119 \degree $\pm$ 13 \degree,33 \degree $\pm$ 10 \degree,102 \degree $\pm$ 10 \degree \在亮区,而在-153 \degree $\pm$ 13 \degree,6 \degree $\pm$ 20 \degree,151 \degree $\pm$ 10 \degree \在暗区。统计分布表明,振荡是由传播慢磁声波遇到TR。这些位置中的一些也可以与驻波慢波相关联。甚至,在给定的时域中,几个位置表现出不同频率的传播振荡和驻波振荡。

英文摘要:

In the present paper, we use Si IV 1393.755 Å spectral line observed by the Interface Region Imaging Spectrograph (IRIS) in the quiet-Sun to determine physical nature of the solar transition region (TR) oscillations. We analyze the properties of these oscillations using wavelet tools (e.g., power, cross-power, coherence, and phase difference) along with the stringent noise model (i.e., power-law + constant). We estimate the period of the intensity and Doppler velocity oscillations at each chosen location in the quiet-Sun (QS) and quantify the distribution of the statistically significant power and associated periods in one bright and two dark regions. In the bright TR region, the mean periods in intensity and velocity are 7 min, and 8 min respectively. In the dark region, the mean periods in intensity and velocity are 7 min, and 5.4 min respectively. We also estimate the phase difference between the intensity and Doppler velocity oscillations at each location. The statistical distribution of phase difference is estimated, which peaks at -119\degree $\pm$ 13\degree, 33\degree $\pm$ 10\degree, 102\degree $\pm$ 10\degree\ in the bright region, while at -153\degree $\pm$ 13\degree, 6\degree $\pm$ 20\degree, 151\degree $\pm$ 10\degree\ in the dark region. The statistical distribution reveals that the oscillations are caused by propagating slow magnetoacoustic waves encountered with the TR. Some of these locations may also be associated with the standing slow waves. Even, in the given time domain, several locations exhibit presence of both propagating and standing oscillations at different frequencies.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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