TRANSPORT MODELING OF L-H TRANSITION AND BARRIER FORMATION

The mechanism of LH transition and transport barrier formation is stud ied by the use of a one-dimensional transport code including plasma ro tation and radial electric field. Particle transport simulation with a fixed temperature profile has indicated that the density profile is q uite sensitive to the edge plasma temperature. When the edge temperatu re exceeds a critical value of about 100 eV, the radial electric field is built up near the plasma edge and the rotation shear reduces the p article transport, The large density gradient due to the reduction of transport enhances the bootstrap current which also contributes to the reduction through less magnetic shear.