PERIODIC SPECTRAL LINE ASYMMETRIES IN SOLAR CORONAL STRUCTURES FROM SLOW MAGNETOACOUSTIC WAVES
PERIODIC SPECTRAL LINE ASYMMETRIES IN SOLAR CORONAL STRUCTURES FROM SLOW MAGNETOACOUSTIC WAVES
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DOI：
10.1088/2041-8205/724/2/l194
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发表时间：
2010-12
期刊：
影响因子：
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通讯作者：
E. Verwichte;M. Marsh;C. Foullon;T. Doorsselaere;I. Moortel;A. Hood;V. Nakariakov
中科院分区：
文献类型：
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作者：
E. Verwichte;M. Marsh;C. Foullon;T. Doorsselaere;I. Moortel;A. Hood;V. Nakariakov
最近对太阳日冕结构中向上移动的准周期强度扰动的光谱观测表明，在它们的脚点附近存在周期线不对称的证据。这些观测结果挑战了传播慢磁声波的强度扰动的既定解释。我们发现，慢波固有的偏向于增强发射线的蓝色翅膀，由于速度和密度扰动的同相行为的发射。我们表明，慢波引起线的不对称性时，发射线的平均振荡周期或当准静态等离子体成分的视线被包括在内。因此，我们得出结论，慢磁声波仍然是一个有效的解释所观察到的准周期强度扰动。
Recent spectral observations of upward moving quasi-periodic intensity perturbations in solar coronal structures have shown evidence of periodic line asymmetries near their footpoints. These observations challenge the established interpretation of the intensity perturbations in terms of propagating slow magnetoacoustic waves. We show that slow waves inherently have a bias toward enhancement of emission in the blue wing of the emission line due to in-phase behavior of velocity and density perturbations. We demonstrate that slow waves cause line asymmetries when the emission line is averaged over an oscillation period or when a quasi-static plasma component in the line of sight is included. Therefore, we conclude that slow magnetoacoustic waves remain a valid explanation for the observed quasi-periodic intensity perturbations.