PRODUCTION OF HE+ IONS BY MUTUAL COLLISIONS BETWEEN METASTABLE HELIUM ATOMS

The time dependence of the He+ ion density has been studied during the decay period of plasmas produced in helium and helium containing 5 × 10-3% neon. The results show that during the early afterglow period the time dependence of the He+ density is determined by the He+ loss processes, while during the late afterglow period this time dependence may be governed by He+ production due to mutual collisions between triplet metastable helium atoms. The experimental conditions for observing the influence of the He+ production process on its decay rate are discussed. © 1969 The American Physical Society.