Numerical Simulation of Density Evolution in JIPP T-2 Tokamak

The density evolution in JIPP T-2 tokamak during gas injection is numerically analyzed using a one dimensional tokamak transport code. The numerical model contains the neoclassical transport including the Ware pinch, empirical anomalous particle and electron heat transports based on Alcator scaling, neutral particle transport and oxygen impurity transport. The Ware pinch effect is significant for the central density rise. The inversion of density profile in the inner region during gas puffing can not be explained. However, the rate of the central density rise observed in the experiment is well explained by the simulation if the energy of recycling neutrals is several tens eV. The effects of ion temperature drift instability on the density evolution are also investigated.