A hybrid Rayleigh-Taylor-current-driven coupled instability in a magnetohydrodynamically collimated cylindrical plasma with lateral gravity
A hybrid Rayleigh-Taylor-current-driven coupled instability in a magnetohydrodynamically collimated cylindrical plasma with lateral gravity
复制标题
具有横向重力的磁流体动力学准直圆柱形等离子体中混合瑞利-泰勒电流驱动的耦合不稳定性
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
P. Bellan
中科院分区：
文献类型：
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作者：
X. Zhai;P. Bellan
本文提出了在横向外重力场中磁约束圆柱形等离子体磁绳表面Rayleigh-Taylor不稳定性的MHD理论。瑞利-泰勒不稳定性被发现耦合到经典的电流驱动的不稳定性，导致一种新的混合不稳定性，不能单独描述的两个不稳定性。横向重力打破了系统的轴对称性，并将所有方位角模式耦合在一起。耦合不稳定性，由螺旋磁场，曲率的圆柱形几何形状，和横向重力的组合产生的，是从根本上不同于经典的磁性瑞利-泰勒不稳定性发生在一个二维平面界面。该理论成功地解释了在加州理工学院等离子体射流实验中观察到的侧向瑞利-泰勒不稳定性[Moser and Bellan，Nature 482，379（2012）]。该理论的潜在应用包括磁控聚变、太阳出射通量、太阳射电、日冕物质抛射以及其他空间和天体物理等离子体过程。
We present an MHD theory of Rayleigh-Taylor instability on the surface of a magnetically confined cylindrical plasma flux rope in a lateral external gravity field. The Rayleigh-Taylor instability is found to couple to the classic current-driven instability, resulting in a new type of hybrid instability that cannot be described by either of the two instabilities alone. The lateral gravity breaks the axisymmetry of the system and couples all azimuthal modes together. The coupled instability, produced by combination of helical magnetic field, curvature of the cylindrical geometry, and lateral gravity, is fundamentally different from the classic magnetic Rayleigh-Taylor instability occurring at a two-dimensional planar interface. The theory successfully explains the lateral Rayleigh-Taylor instability observed in the Caltech plasma jet experiment [Moser and Bellan, Nature 482, 379 (2012)]. Potential applications of the theory include magnetic controlled fusion, solar emerging flux, solar prominences, coronal mass ejections, and other space and astrophysical plasma processes.