An implicit Monte Carlo method for simulation of impurity transport in divertor plasma

A new ''implicit'' Monte Carlo (IMC) method has been developed to simulate ionization and recombination processes of impurity ions in divertor plasmas. The IMC method takes into account many ionization and recombination processes during a time step Delta t. The time step is not limited by a condition, Delta t much less than tau(min) (tau(min); the minimum characteristic time of atomic processes), which is forced to be adopted in conventional Monte Carlo methods. We incorporate this method into a one-dimensional impurity transport model. In this transport calculation, impurity ions are followed with the time step about 10 times larger than that used in conventional methods. The average charge state of impurities, [Z], and the radiative cooling rate, L(T-e), are calculated at the electron temperature T-e in divertor plasmas. These results are compared with thosed obtained from the simple noncoronal model. (C) 1997 Academic Press.