The effect of density stratification on the transverse oscillations of two parallel coronal loops
The effect of density stratification on the transverse oscillations of two parallel coronal loops
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DOI：
10.1051/0004-6361/201014055
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发表时间：
2010-06
影响因子：
6.5
通讯作者：
D. Robertson;M. Ruderman;Y. Taroyan
中科院分区：
文献类型：
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作者：
D. Robertson;M. Ruderman;Y. Taroyan
在太空任务中，日冕磁环的横向振荡是经常观察到的。自从第一次观测以来，这些振荡就被解释为磁管的扭结振荡。有时观测到两个或多个日冕环的集体振荡。这使得一些平行磁管的集体振荡理论的发展是可取的。这一理论发展的另一个原因是，有证据表明，至少有一些日冕环不是单片的，而是由许多细磁线组成的。本文建立了两根平行磁管的扭结振荡随磁管密度变化的线性理论。利用渐近方法导出了控制两管集体扭结振荡的方程组。该系统用于研究密度变化对集体振荡本征频率的影响。讨论了所得结果对日冕地震学的意义。
Transverse oscillations of coronal magnetic loops are routinely observed during the space missions. Since the first observation these oscillations were interpreted in terms of kink oscillations of magnetic tubes. Sometimes collective oscillations of two or more coronal loops are observed. This makes the development of theory of collective oscillations of a few parallel magnetic tubes desirable. Another reason for the development of this theory is that there are evidences that at least some coronal loops are not monolithic but consist of many thin magnetic threads. In this paper the linear theory of kink oscillations of two parallel magnetic tubes with the density varying along the tubes is developed. The asymptotic method is used to derive the system of equations governing the collective kink oscillations of two tubes. This system is used to study the effect of density variation on the eigenfrequencies of collective oscillations. The implication of the obtained results on coronal seismology is discussed.