Scaling of H-mode energy confinement with I_P and B_T in the MAST spherical tokamak

摘要

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 I_P is weaker than linear while the dependence on toroidal magnetic field B_T is stronger than linear, in contrast to conventional energy confinement scalings. These I_P and B_T dependences have also been confirmed by single parameter scans. Transport analysis indicates that the strong B_T scaling of energy confinement could possibly be explained by weaker q and stronger v_* dependence of heat diffusivity in comparison with conventional tokamaks.