The dependences of energy confinement on plasma current and toroidal magnetic field have been investigated in the MAST spherical tokamak in H-mode plasmas. Multivariate fits show that the dependence of energy confinement time on plasma current Ip is weaker than linear while the dependence on toroidal magnetic field BT is stronger than linear, in contrast to conventional energy confinement scalings. These Ip and BT dependences have also been confirmed by single parameter scans. Transport analysis indicates that the strong BT scaling of energy confinement could possibly be explained by weaker q and stronger ν* dependence of heat diffusivity in comparison with conventional tokamaks.
MAST球形托卡马克装置中，在H模等离子体条件下，对能量约束对等离子体电流和环向磁场的依赖性进行了研究。多变量拟合结果表明，能量约束时间对等离子体电流Ip的依赖性弱于线性关系，而对环向磁场BT的依赖性则强于线性关系，这与常规托卡马克的能量约束定标律形成对比。通过单参数扫描也证实了Ip和BT的上述依赖性。输运分析表明，与常规托卡马克相比，热扩散系数对安全因子q的依赖性较弱、对归一化碰撞频率ν*的依赖性较强，这可能是强BT定标关系的物理解释。