Numerical study of overpopulation density for laser oscillation in recombining hydrogen plasmas

• Published in: Journal of quantitative spectroscopy & radiative transfer Vol. 29; no. 6; pp. 553 - 559
• Main Authors: Oda, Toshiatsu, Furukane, Utarō
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.1983
• ISSN: 0022-4073; 1879-1352
• DOI: 10.1016/0022-4073(83)90133-4

Overpopulation densities Δ n itij , which are defined as the differences between the population densities per unit statistical weight of the upper and lower excited levels i and j, are calculated as a function of the electron density n e for various electron temperatures T e in recombining hydrogen plasmas. Calculation have been made for line pairs with principal quantum numbers (2 ,3), (3, 4) and (4, 5). The effect of the ground-level population density n 1 on Δ n ij is calculated. In this calculation, the atom-atom collision and the self-absorption of the resonance lines are taken into account. The n 1-dependence of Δ n ij remains almost constant until the self-absorption becomes significant. The threshold condition for laser oscillation is discussed in relation to the calculated Δ n ij . Laser oscillation is possible for the line pair (2, 3) at an electron density and temperature higher than for the other pairs (3, 4) and (4, 5) when self-absorption is negligible.