CONTINUOUS EMISSION DUE TO RADIATIVE ION-ATOM ASSOCIATION AND CHARGE-EXCHANGE IN WEAKLY IONIZED PLASMAS OF H, HE, LI AND NA

The contribution of radiative charge exchange and radiative associatio n in symmetrical ion-atom collisions to continuous EM radiation from w eakly ionized gaseous plasmas has been considered within the semiclass ical adiabatic theory. The differential (in lambda) cross sections for spontaneous photon emission and the general expressions for the spect ral coefficients of emission and absorption are given. The hydrogen an d helium plasmas that are representative of two different optical type s of gaseous medium have been studied in a broad range of T and lambda , 4000 less than or equal to T (K) less than or equal to 20 000 and 20 0 less than or equal to A (nm) less than or equal to 1000. The domain of T and lambda, where ion-atom collisions contribute significantly to continuous plasma spectra, has been established. The case of weakly i onized alkali metal plasmas of Li and Na has been studied in the same interval of lambda but at lower temperatures, 1500 less than or equal to 7 (K) less than or equal to 3500. The relevance of the results to s tudies of laboratory plasmas is discussed.