Damping and power spectra of quasi-periodic intensity disturbances above a solar polar coronal hole
Damping and power spectra of quasi-periodic intensity disturbances above a solar polar coronal hole
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DOI：
10.1088/1674-4527/16/6/093
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发表时间：
2016-02
影响因子：
1.8
通讯作者：
Fangran Jiao;L. Xia;Zhenghua Huang;Bo Li;H. Fu;D. Yuan;K. Chandrashekhar
中科院分区：
文献类型：
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作者：
Fangran Jiao;L. Xia;Zhenghua Huang;Bo Li;H. Fu;D. Yuan;K. Chandrashekhar
我们研究了在AIA 171 Å和193 Å波段可以看到的太阳极日冕洞上方的强度扰动，旨在提供更多关于其物理性质的见解。研究了频率为0.07 ~ 10.5 mHz的强度扰动的阻尼和功率谱。强度扰动的阻尼往往在较低的频率下更强，它们在980″以下的阻尼行为（为了比较，边缘在945″）与上面发生的情况不同。AIA 171 Å与AIA 193 Å的强度扰动阻尼无显著差异。强度扰动的功率谱指标在AIA 171 Å中略小于AIA 193 Å，但相差在一个标准差以内。在较低的高度，在8-40分钟的周期范围内，功率谱中存在额外的增强分量。针状体的功率谱与其相关的强度扰动高度相关，这表明强度扰动的功率谱可能是针状体和波活动的混合。我们认为，在极日冕洞中的每一次强度扰动都可能是一系列独立的慢磁声波。
We study intensity disturbances above a solar polar coronal hole that can be seen in the AIA 171 Å and 193 Å passbands, aiming to provide more insights into their physical nature. The damping and power spectra of the intensity disturbances with frequencies from 0.07 mHz to 10.5 mHz are investigated. The damping of the intensity disturbances tends to be stronger at lower frequencies, and their damping behavior below 980″ (for comparison, the limb is at 945″) is different from what happens above. No significant difference is found between the damping of the intensity disturbances in the AIA 171 Å and that in the AIA 193 Å. The indices of the power spectra of the intensity disturbances are found to be slightly smaller in the AIA 171 Å than in the AIA 193 Å, but the difference is within one standard deviation. An additional enhanced component is present in the power spectra in a period range of 8–40 min at lower heights. The power spectra of a spicule is highly correlated with its associated intensity disturbance, which suggests that the power spectra of the intensity disturbances might be a mixture of spicules and wave activities. We suggest that each intensity disturbance in the polar coronal hole is possibly a series of independent slow magnetoacoustic waves triggered by spicular activities.