title: A collisional radiative model of hydrogen plasmas developed for diagnostic purposes of negative ion sources.
abstract: A collisional radiative model of low-pressure hydrogen plasmas is elaborated and applied in optical emission spectroscopy diagnostics of a single element of a matrix source of negative hydrogen ions. The model accounts for the main processes determining both the population densities of the first ten states of the hydrogen atom and the densities of the positive hydrogen ions H(+), H2 (+), and H3 (+). In the calculations, the electron density and electron temperature are varied whereas the atomic and molecular temperatures are included as experimentally obtained external parameters. The ratio of the Hα to Hβ line intensities is calculated from the numerical results for the excited state population densities, obtained as a solution of the set of the steady-state rate balance equations. The comparison of measured and theoretically obtained ratios of line intensities yields the values of the electron density and temperature as well as of the degree of dissociation, i.e., of the parameters which have a crucial role for the volume production of the negative ions.
authors.affiliation: Faculty of Physics, Sofia University, BG-1164 Sofia, Bulgaria.
authors.forename: Snejana
authors.initials: S
authors.lastname: Iordanova
authors.affiliation: Faculty of Physics, Sofia University, BG-1164 Sofia, Bulgaria.
authors.forename: Tsvetelina
authors.initials: T
authors.lastname: Paunska