STATISTICAL EVIDENCE FOR THE EXISTENCE OF ALFVÉNIC TURBULENCE IN SOLAR CORONAL LOOPS
STATISTICAL EVIDENCE FOR THE EXISTENCE OF ALFVÉNIC TURBULENCE IN SOLAR CORONAL LOOPS
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DOI：
10.1088/0004-637x/797/1/7
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发表时间：
2014-11
期刊：
影响因子：
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通讯作者：
Jiajia Liu;S. McIntosh;I. De Moortel;J. Threlfall;C. Bethge
中科院分区：
文献类型：
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作者：
Jiajia Liu;S. McIntosh;I. De Moortel;J. Threlfall;C. Bethge
最近的观测表明，能够携带大量能量的波在整个日冕中无处不在。然而，这种波能量是如何耗散的（在什么时间尺度和长度尺度上）并释放到等离子体中的问题在很大程度上仍然没有答案。分析和数值模型先前都表明，阿尔夫维尼克湍流可能不仅在快速太阳风的产生中起着关键作用，而且在日冕环的加热中也起着关键作用。为了弥合理论和观测之间的差距，我们扩展了最近的一项研究，通过分析37个明显孤立的日冕循环使用的数据从日冕多通道偏振仪仪器。我们观察到Alfvénic扰动的相速度范围从250到750 km s-1和周期从140到270 s的选择的循环。虽然过剩的高频波功率的顶点附近观察到的一些环路（暂时支持发病的Alfvénic湍流），我们表明，这种过剩取决于环路长度和所观察到的振荡的波长。在推导环的长度/波长比和增强的波功率之间的比例关系在环的顶点，并从与这些环的线宽的分析，我们的研究结果是支持的Alfvénic湍流在冠状环的存在。
Recent observations have demonstrated that waves capable of carrying large amounts of energy are ubiquitous throughout the solar corona. However, the question of how this wave energy is dissipated (on which timescales and length scales) and released into the plasma remains largely unanswered. Both analytic and numerical models have previously shown that Alfvénic turbulence may play a key role not only in the generation of the fast solar wind, but in the heating of coronal loops. In an effort to bridge the gap between theory and observations, we expand on a recent study by analyzing 37 clearly isolated coronal loops using data from the Coronal Multi-channel Polarimeter instrument. We observe Alfvénic perturbations with phase speeds which range from 250 to 750 km s−1 and periods from 140 to 270 s for the chosen loops. While excesses of high-frequency wave power are observed near the apex of some loops (tentatively supporting the onset of Alfvénic turbulence), we show that this excess depends on loop length and the wavelength of the observed oscillations. In deriving a proportional relationship between the loop length/wavelength ratio and the enhanced wave power at the loop apex, and from the analysis of the line widths associated with these loops, our findings are supportive of the existence of Alfvénic turbulence in coronal loops.