Model validation for radial electric field excitation during L-H transition in JFT-2M tokamak

In this paper, we elaborate the electric feld excitation mechanism during the L-H transition in the JFT-2M tokamak. Using time derivative of the Poisson's equation, models of the radial electric feld excitation is examined. The sum of the loss-cone loss current and the neoclassical bulk viscosity current is found to behave as the experimentally evaluated radial current that excites the radial electric feld. The turbulent Reynolds stress only plays a minor role. The wave convection current that produces a negative current at the edge can be important to explain the ambipolar condition in the L-mode.