Modeling of global particle balance in steady-state magnetic fusion devices – Analysis of the recent data from the TRIAM-1M tokamak

Global particle balance analysis has been conducted to interpret the data from TRIAM-1M experiments, using a zero-dimension four-reservoir model to calculate the particle inventories in the core plasma, SOL region, gas phase, and wall materials. Two cases have been examined: a relatively short pulse (∼30 s) but high density (∼1019 1/m3) LHCD discharge at 8.2 GHz; and a long pulse (∼4000 s) but low density (∼1018 1/m3) LHCD discharge at 2.45 GHz. Model calculations have reproduced well the core and SOL plasma densities. Also, the observed wall pumping effects have been analyzed by this model. Measured and model prediction on the wall pumping rate are 4×1017 and 4.4×1017 1/m2/s at 8.2 GHz, and 1.5×1016 and 1.8×1016 1/m2/s at 2.45 GHz, respectively, both relatively good agreements. Also, a parameter sensitivity check has been conducted, and modeling results clearly indicate that the steady state core plasma density decreases with increasing the codeposition probability.