Comparison of damping models for kink oscillations of coronal loops
Comparison of damping models for kink oscillations of coronal loops
复制标题
日冕环扭结振荡阻尼模型的比较
DOI：
10.1093/mnras/stad2598
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发表时间：
2023
影响因子：
4.8
通讯作者：
Zhong Y
中科院分区：
文献类型：
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作者：
Zhong Y
太阳日冕环的扭折振荡由于其诊断日冕中等离子体参数的潜力而引起人们的强烈兴趣。扭结振荡阻尼时间的精确测量对于精确的地震诊断（如横向密度分布）和确定阻尼机制至关重要。大振幅快速衰减扭结振荡的研究表明，无论是指数阻尼模型和广义模型（高斯和指数阻尼模式组成）符合观察到的阻尼配置文件足够好。然而，最近理论上表明，从衰减状态到无衰减状态的过渡可以用超指数阻尼模型来表征。在这项工作中，我们重新分析一个样本的衰减扭结振荡事件，并利用马尔可夫链蒙特卡罗贝叶斯方法比较指数，高斯指数，和超指数阻尼模型。结果表明，在10个分析振荡中，有7个振荡的优先阻尼模型是超指数模型。在两个事件中，优先阻尼是指数的，在一个事件中，它是高斯指数。这一发现表明超指数阻尼模型的可扩展性。在分析大量事件时，特别是在估计阻尼时间及其与振荡周期和振幅相关的经验标度时，以及在地震学反演中，需要考虑非指数阻尼模式的可能性。
Kink oscillations of solar coronal loops are of intense interest due to their potential for diagnosing plasma parameters in the corona. The accurate measurement of the kink oscillation damping time is crucial for precise seismological diagnostics, such as the transverse density profile, and for the determination of the damping mechanism. Previous studies of large-amplitude rapidly decaying kink oscillations have shown that both an exponential damping model and a generalized model (consisting of Gaussian and exponential damping patterns) fit observed damping profiles sufficiently well. However, it has recently been shown theoretically that the transition from the decaying regime to the decayless regime could be characterized by a superexponential damping model. In this work, we reanalyse a sample of decaying kink oscillation events, and utilize the Markov chain Monte Carlo Bayesian approach to compare the exponential, Gaussian–exponential, and superexponential damping models. It is found that in 7 out of 10 analysed oscillations, the preferential damping model is the superexponential one. In two events, the preferential damping is exponential, and in one it is Gaussian–exponential. This finding indicates the plausibility of the superexponential damping model. The possibility of a non-exponential damping pattern needs to be taken into account in the analysis of a larger number of events, especially in the estimation of the damping time and its associated empirical scalings with the oscillation period and amplitude, and in seismological inversions.