Hybrid Monte Carlo - fluid modeling network for an argon/hydrogen direct current glow discharge

A hybrid modeling network, consisting of several Monte Carlo and fluid models, is developed for a dc glow discharge: typically used for mass spectrometry, in a mixture of Ar with 1% H-2. The species described in the model are: electrons; Ar+ ions and fast Ar atoms; ArH+, H+, H-2(+) and H-3(+) ions; H atoms; and H-2 molecules; as well as Ar metastable atoms. Sixty-three reactions are taken into account in the model. The calculated densities of the various plasma species are presented. The electrons and Ar+ ions are the dominant charged species in the plasma, with densities in the order of 10(11) cm(-3). Furthermore, the ArH+ and H-3(+) ions have a relatively high density (in the order 3 of a few 10(10) cm(-3)), whereas the H+ and H-2(+) densities are negligible (order of 10(6)-10(7) cm(-3)). The dissociation degree of the H-2 molecules was calculated to be very low (approx. 0.02%), yielding H-2 and H densities in the order of 10(14) and 10(11) cm(-3), respectively. The relative contribution of different production and loss processes of the electrons. different ions, H atoms, H-2 molecules and Ar metastable atoms are also calculated. Finally, a comparison is made between a pure Ar discharge and a glow discharge in a mixture of Ar + 1% H-2. (C) 2002 Elsevier Science B.V. All rights reserved.