Plasma rotation in a quasi-symmetric stellarator
Plasma rotation in a quasi-symmetric stellarator
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准对称仿星器中的等离子体旋转
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
P. Helander
中科院分区：
文献类型：
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作者：
A. Simakov;P. Helander
一般环向磁场中的平衡等离子体旋转几乎总是亚音速的，这是由小离子-回旋半径膨胀中碰撞粒子输运最低阶双极性的要求决定的。只有在准对称场中，碰撞粒子输运本质上是双极性的，等离子体才能自由旋转，然后只能在准对称方向上旋转。在这种情况下，音速旋转速度是允许的。本文研究了准轴对称场中旋转的影响，发现当旋转速度明显超过抗磁速度时，对称性被打破，导致非本质双极性1/ν输运态的再现。幸运的是，这种输运与旋转马赫数的四次方成比例，并且在大多数感兴趣的等离子体中预计是适度的。
The equilibrium plasma rotation in a general toroidal magnetic field is nearly always subsonic and is determined by the requirement that the collisional particle transport should be ambipolar in lowest order in the small-ion-gyroradius expansion. Only in quasi-symmetric fields, where collisional particle transport is intrinsically ambipolar, can the plasma rotate freely and then only in the quasi-symmetry direction. Sonic rotation velocities are allowed in this case. In this paper the effect of rotation in a quasi-axisymmetric field is investigated, and it is found that the symmetry is broken when the rotation speed exceeds the diamagnetic speed appreciably, leading to reappearance of the non-intrinsically ambipolar 1/ν-transport regime. Fortunately, this transport scales with the fourth power of the rotation Mach number and is expected to be modest in most plasmas of interest.