Spatial damping of propagating kink waves due to mode coupling
Spatial damping of propagating kink waves due to mode coupling
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DOI：
10.1051/0004-6361/201117979
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发表时间：
2012-03
影响因子：
6.5
通讯作者：
D. Pascoe;A. Hood;I. Moortel;A. Wright
中科院分区：
文献类型：
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作者：
D. Pascoe;A. Hood;I. Moortel;A. Wright
目标。我们调查传播横向速度振荡的阻尼过程，观察到是无处不在的日冕，由于模式耦合。方法.我们对具有圆柱形密度结构的低β日冕等离子体中传播的足点驱动横波进行了3D数值模拟。模式耦合在一个不均匀的层导致耦合的扭结模式的阿尔芬模式，观察到的衰减的横向扭结振荡。结果我们考虑了空间阻尼分布，发现形式为exp（−z/Lg）的高斯阻尼分布与我们的数值数据最一致，而不是简正模分析中使用的形式为exp（−z/Ld）的指数阻尼分布。我们的研究结果强调，司机本身的性质将有一个观察到的传播扭结波的重大影响。结论.我们的研究表明，这种修改后的阻尼配置文件时，应考虑到使用冠状地震推断本地等离子体的性能，从观察到的阻尼振荡。
Aims. We investigate the damping process for propagating transverse velocity oscillations, observed to be ubiquitous in the solar corona, due to mode coupling. Methods. We perform 3D numerical simulations of footpoint-driven transverse waves propagating in a low β coronal plasma with a cylindrical density structure. Mode coupling in an inhomogeneous layer leads to the coupling of the kink mode to the Alfven mode, observed as the decay of the transverse kink oscillations. Results. We consider the spatial damping profile and find a Gaussian damping profile of the form exp(−z/Lg) to be the most congruent with our numerical data, rather than the exponential damping profile of the form exp(−z/Ld) used in normal mode analysis. Our results highlight that the nature of the driver itself will have a substantial influence on observed propagating kink waves. Conclusions. Our study suggests that this modified damping profile should be taken into account when using coronal seismology to infer local plasma properties from observed damped oscillations.