Observations and mode identification of sausage waves in a magnetic pore
Observations and mode identification of sausage waves in a magnetic pore
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DOI：
10.1051/0004-6361/201425096
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发表时间：
2015-07
影响因子：
6.5
通讯作者：
M. Moreels;N. Freij;R. Erdélyi;T. Doorsselaere;G. Verth
中科院分区：
文献类型：
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作者：
M. Moreels;N. Freij;R. Erdélyi;T. Doorsselaere;G. Verth
目标。我们的目标是只使用一个高度的强度图像来确定磁孔中振荡的相速度。这些观测是使用Swedisch 1-m太阳望远镜上的CRISP成像光谱偏振仪获得的，显示了磁孔中横截面面积和强度的变化。方法：研究方法。我们设计并测试了一种观测方法，以提取对地震学重要的波参数。我们将磁孔模拟为一个直柱体，在通量管内外都有均匀的等离子体，并识别出不同的波模。利用解析表达式，我们能够区分快模和慢模，并得到振荡的相速度。结果。我们发现观测到的振荡是慢模，相速度约为5公里S-1。我们也有强有力的证据表明，这些振荡是驻波。
Aims. We aim to determine the phase speed of an oscillation in a magnetic pore using only intensity images at one height. The observations were obtained using the CRisp Imaging SpectroPolarimeter at the Swedisch 1-m Solar Telescope and show variations in both cross-sectional area and intensity in a magnetic pore. Methods. We have designed and tested an observational method to extract the wave parameters that are important for seismology. We modelled the magnetic pore as a straight cylinder with a uniform plasma both inside and outside the flux tube and identify different wave modes. Using analytic expressions, we are able to distinguish between fast and slow modes and obtain the phase speed of the oscillations. Results. We found that the observed oscillations are slow modes with a phase speed around 5 km s-1. We also have strong evidence that the oscillations are standing harmonics.