NUMERICAL STUDY OF THE EARLY POPULATION DENSITY RELAXATION OF THERMAL HYDROGEN PLASMAS

Abstract : The purpose of this investigation was to examine the early relaxation of the population density distribution of a thermal hydrogen plasma. The system of rate equations describing the transient behavior of all quantum levels was used and solved numerically. Three hypothetical hydrogen plasmas were studied, each with an excitation temperature of 10,000 degrees K. Two of the plasmas differed only by the transition probability of the quasi-metastable 2S1/2 eigenstate, whereas the third case used a different initial population density distribution. The plasmas were used to study the fundamental consistency of the mathematical model, the existence and location of the critical level, relaxation to the quasi-steady state, and a quantitative study of the effects of the quasi- metastable level on the excited state population density distribution. The results show that the model is consistent with fundamental theory under strong collision dominance and that the critical level does exist at that level predicted by earlier investigators.