Magnetic Rayleigh-Taylor instability at a contact discontinuity with an oblique magnetic field
Magnetic Rayleigh-Taylor instability at a contact discontinuity with an oblique magnetic field
复制标题
倾斜磁场接触不连续处的磁瑞利-泰勒不稳定性
DOI：
10.1051/0004-6361/201936490
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发表时间：
2020
影响因子：
6.5
通讯作者：
Vickers E
中科院分区：
文献类型：
--
作者：
Vickers E
目的我们研究在不可压缩极限下渗透有倾斜均匀磁场的密度界面处磁瑞利-泰勒不稳定性的本质。方法使用线性化理想不可压缩磁流体动力学方程组，通过在界面处施加必要的连续性条件，推导出接触不连续性扰动的色散关系。频率的虚部描述了由于不稳定性而导致的波的增长速率。通过数值求解色散关系来研究波的生长速率。结果平行磁场中存在的波变得不稳定的临界波数由于磁场倾斜而消失。相反，波对于所有波数来说都是不稳定的。理论结果用于诊断突出螺纹中的磁场结构。当我们将理论结果应用于观测到的日珥羽流中的波时，我们获得了从 0.5° 到 30° 的各种场倾角。这些结果凸显了我们的研究提供的诊断可能性。
AimsWe investigate the nature of the magnetic Rayleigh–Taylor instability at a density interface that is permeated by an oblique homogeneous magnetic field in an incompressible limit.MethodsUsing the system of linearised ideal incompressible magnetohydrodynamics equations, we derive the dispersion relation for perturbations of the contact discontinuity by imposing the necessary continuity conditions at the interface. The imaginary part of the frequency describes the growth rate of waves due to instability. The growth rate of waves is studied by numerically solving the dispersion relation.ResultsThe critical wavenumber at which waves become unstable, which is present for a parallel magnetic field, disappears because the magnetic field is inclined. Instead, waves are shown to be unstable for all wavenumbers. Theoretical results are applied to diagnose the structure of the magnetic field in prominence threads. When we apply our theoretical results to observed waves in prominence plumes, we obtain a wide range of field inclination angles, from 0.5° up to 30°. These results highlight the diagnostic possibilities that our study offers.