Transport analysis of high-beta plasmas on LHD

Local transport properties of high-beta plasmas in the Large Helical Device are studied by comparing the beta dependence of the experimental results with that of the gyro-reduced Bohm-type transport coefficients. The gradual degradation of global confinement in the high-beta regime seems to be mainly caused by the increment in the local transport at the peripheral region. Effects of the resistive pressure-gradient-driven (g-mode) turbulence on the peripheral transport are also studied. The comparison of the experimental transport coefficients and the calculation results shows that the resistive g-mode can be considered as one of the causes of this degradation.