Modelling of the closed ICP

Summary form only given. The closed inductively coupled plasma (ICP) may serve as an efficient light source. In order to get insight into the influence of filling gas characteristics on plasma properties a plasma simulation program has been developed. The backbone of this program is a powerful Navier-Stokes solver, based upon Patankar´s SIMPLE algorithm. The plasmas under study contain pure argon with filling pressures from 1 kPa to 10 kPa. Argon plasmas have very poor lighting properties but are extremely valuable in the study of the influence of deviations from local thermal equilibrium. Calculations reveal that for argon the bulk velocity is small and of little importance. The calculated heavy particle temperature and electron density fairly agree with experimental data. The predicted spatial dependence is not satisfying: the calculated profiles are too pronounced and have maximums nearer to the wall than observed experimentally. This has led to the belief that at least one more mechanism must be taken into account. Candidates are molecular processes and increased escape of radiation due to pressure broadening. To check the conjecture that pressure broadening is important, the focus is on the 1 kPa plasma in which case this mechanism is least contributing.