A prototype of an electric-discharge gas flow oxygen−iodine laser: I. Modeling of the processes of singlet oxygen generation in a transverse cryogenic slab RF discharge

• Published in: Plasma physics reports 2017-03, Vol.43 (3), p.330-339
• Main Authors: Vagin, N. P., Ionin, A. A., Kochetov, I. V., Napartovich, A. P., Sinitsyn, D. V., Yuryshev, N. N.
• Format: Article
• Language: English
• Subjects: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; Atomic; COMPUTERIZED SIMULATION; Conduction cooling; Conduction heating; Conductive heat transfer; CRYOGENICS; ELECTRIC DISCHARGES; ELECTRODES; Evolution; GAS COOLING; GAS FLOW; Gas heating; Gas temperature; HEATING; HELIUM; Iodine; IODINE LASERS; KINETICS; Laser applications; Laser Plasma; Molecular; Optical and Plasma Physics; OXYGEN; Oxygen enrichment; PARTIAL PRESSURE; Physics; Physics and Astronomy; PLASMA; Plug flow; Radio frequency discharge; RF discharge-pumped lasers; RF SYSTEMS; Singlet oxygen; SLABS; THERMAL CONDUCTION
• ISSN: 1063-780X; 1562-6938
• DOI: 10.1134/S1063780X17030151

The existing kinetic model describing self-sustained and electroionization discharges in mixtures enriched with singlet oxygen has been modified to calculate the characteristics of a flow RF discharge in molecular oxygen and its mixtures with helium. The simulations were performed in the gas plug-flow approximation, i.e., the evolution of the plasma components during their motion along the channel was represented as their evolution in time. The calculations were carried out for the O 2 : He = 1: 0, 1: 1, 1: 2, and 1: 3 mixtures at an oxygen partial pressure of 7.5 Torr. It is shown that, under these conditions, volumetric gas heating in a discharge in pure molecular oxygen prevails over gas cooling via heat conduction even at an electrode temperature as low as ~100 K. When molecular oxygen is diluted with helium, the behavior of the gas temperature changes substantially: heat removal begins to prevail over volumetric gas heating, and the gas temperature at the outlet of the discharge zone drops to ~220–230 K at room gas temperature at the inlet, which is very important in the context of achieving the generation threshold in an electric-discharge oxygen−iodine laser based on a slab cryogenic RF discharge.