Recombination and energy balance in a decaying plasma I. H—H + — e plasma

Abstract

The thermal economy of a decaying H — H + — e plasma is discussed in detail, particular attention being paid to a plasma which is magnetically confined so that only the atoms can strike the containing walls. It is pointed out that the relaxation times for the temperatures, T e and T i of electrons and ions are commonly shorter than the relaxation times for the number densities, n ( c ) and n (1), of electrons and atoms, so that as the plasma decays these temperatures fall through quasi-equilibrium values. The quasi-equilibrium T e and T i and the corresponding collisional-radiative recombination coefficient a are calculated for a wide range of optically thin and optically thick plasmas. A comparison is made with the experimental data of Hinnov & Hirschberg (1962). Satisfactory agreement is obtained. Very dense plasmas in which ionizing collisions are important are briefly considered.