Modelling of gas target experiment in TPD

The characteristic properties of plasma in gas divertor was investigated by complementary studies of computer simulation and the simulation of gas target using the stationary high density plasma generator TPD-I. The simulation of gas target was carried by applicating two dimensional flux code (B2 code) to TPD-I. The plasma was defined as the simulation model as an axisymmetric cylinder and only one flux of helium plasma. The ionization, charge exchange and recombination were considered in atom-molecule process. With increasing the target gas pressure, the electron density increased and the electron and ion temperature decreased toward target, and the ion temperature decreased drastically at inflow entrance, although the electron temperature was not changed at the local point. Permeation of target gas to the plasma has large effect on the plasma cooling. But 'Detached Plasma' was not observed by the simulation but observed by the experiment. To analyse them in detail, the precision modelling should be obtained by introducing the excitation and transportation process of neutral gas and by comparing between experimental result and them. (S.Y.)