Effect of bootstrap current on MHD equilibrium beta limit in heliotron plasmas
Effect of bootstrap current on MHD equilibrium beta limit in heliotron plasmas
复制标题
自举电流对日光管等离子体中 MHD 平衡 β 极限的影响
DOI：
10.1088/0029-5515/41/1/305
复制
发表时间：
2001
期刊：
影响因子：
3.3
通讯作者：
N.Nakajima
中科院分区：
文献类型：
--
作者：
K.Y. Watanabe;N.Nakajima
通过迭代计算MHD平衡和高β日光管等离子体中的一致自举电流，系统地研究了自举电流对MHD平衡β极限的影响。 LHD 机器被视为具有 L = 2 平面轴的标准配置日光管。研究了真空磁结构、压力分布和垂直场控制方法的影响。与无电流情况相比，具有一致自举电流的平衡 β 极限对有限 β 的磁轴位置非常敏感。对于磁轴在环面中向内移动的真空配置，即使在高β状态下，自举电流也会流动以增加旋转变换，从而导致平衡β极限的增加。相反，对于磁轴在环面中向外移动的真空结构，即使在低β状态下，自举电流也会流动以减少旋转变换；因此，随着 beta 的增加，沙夫拉诺夫位移会加速增加，从而导致平衡 beta 极限的降低。压力分布和垂直场控制方法通过有限贝塔磁轴的位置影响平衡贝塔极限。这些特性与器件参数（例如磁场强度）和低碰撞状态下的器件尺寸无关。
The effect of bootstrap current on the beta limit of MHD equilibria is studied systematically by an iterative calculation of MHD equilibrium and the consistent bootstrap current in high beta heliotron plasmas. The LHD machine is treated as a standard configuration heliotron with an L = 2 planar axis. The effects of vacuum magnetic configurations, pressure profiles and the vertical field control method are studied. The equilibrium beta limit with consistent bootstrap current is quite sensitive to the magnetic axis location for finite beta, compared with the currentless cases. For a vacuum configuration with the magnetic axis shifted inwards in the torus, even in the high beta regimes, the bootstrap current flows to increase the rotational transform, leading to an increase in the equilibrium beta limit. On the contrary, for a vacuum configuration with the magnetic axis shifted outwards in the torus, even in the low beta regimes, the bootstrap current flows so as to reduce the rotational transform; therefore, there is an acceleration of the Shafranov shift increase as beta increases, leading to a decrease in the equilibrium beta limit. The pressure profiles and vertical field control methods influence the equilibrium beta limit through the location of the magnetic axis for finite beta. These characteristics are independent of both device parameters, such as magnetic field strength, and device size in the low collisional regime.