Rayleigh-Taylor instabilities with sheared magnetic fields in partially ionised plasmas
Rayleigh-Taylor instabilities with sheared magnetic fields in partially ionised plasmas
复制标题
部分电离等离子体中剪切磁场的瑞利-泰勒不稳定性
DOI：
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
M. Collados
中科院分区：
文献类型：
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作者：
M. Ruderman;I. Ballai;E. Khomenko;M. Collados
目标。在本研究中，我们研究了出现在切向不连续处的磁瑞利-泰勒不稳定性的性质
Aims. In the present study we investigate the nature of the magnetic Rayleigh-Taylor instability appearing at a tangential discontinuity
in a partially ionised plasma when the effect of magnetic shear is taken into account.
Methods. The partially ionised character of the plasma is described by the ambipolar diffusion in the induction equation. The dynamics
of the plasma is investigated in a single-fluid approximation. After matching the solutions on both sides of the interface we derive a
dispersion equation and calculate the instability increment using analytical methods for particular cases of parameters, and numerical
investigation for a wide range of parameters.
Results. We calculated the dependence of the instability increment on the perturbation wavenumber. We also calculated the dependence
of the maximum instability increment on the shear angle of the magnetic field for various values of the ionisation degree.
Conclusions. Our results show that the Rayleigh-Taylor instability becomes sensitive to the degree of plasma ionisation only for
plasmas with small values of plasma beta and in a very weakly ionised state. Perturbations are unstable only for those wavenumbers
that are below a cut-off value.