Non-Axisymmetric Alfvén Wave Excited by a Helical Coupler in an Inhomogeneous Plasma
Non-Axisymmetric Alfvén Wave Excited by a Helical Coupler in an Inhomogeneous Plasma
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非均匀等离子体中螺旋耦合器激发的非轴对称阿尔芬波
DOI：
10.1143/jjap.20.2171
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发表时间：
1980
影响因子：
1.5
通讯作者：
A. Tsushima
中科院分区：
文献类型：
--
作者：
Y. Amagishi;M. Inutake;T. Akitsu;A. Tsushima
用螺旋耦合器在有限β空间和被导电壁包围的圆柱形非均匀等离子体中激发非轴对称Alfvén波。由两个对称螺旋绕组组成的螺旋耦合器具有很强的传播方向性，m=-1模的慢波和m=+1模的快波可以同时从耦合器发射，但沿沿着静磁场的相反方向传播。色散关系，包括两种模式的衰减长度进行了比较与伍兹的磁流体动力学理论的假设适当的边界条件。作为一种非线性现象，当抽运频率接近或高于离子回旋频率时，观察到m=-1模的亚谐波慢Alfvén波。
Non-axisymmetric Alfvén waves are excited with a helical coupler in a finite beta and a cylindrical inhomogeneous plasma surrounded by a conducting wall. The helical coupler, which consists of two symmetrical helical windings, exhibits a strong propagation directionality; slow waves of the m=-1 mode and fast waves of the m=+1 mode can be launched simultaneously from the coupler, but propagate in opposite directions along the static magnetic field. Dispersion relations including the attenuation length for both modes are compared with a magnetohydrodynamic theory given by Woods on the assumption of appropriate boundary conditions. As a nonlinear phenomenon, subharmonic slow Alfvén waves of the m=-1 mode have been observed when the pump frequency is close to or above the ion cyclotron frequency.