Talk · International Conference on Pulsed Lasers and Laser Applications · December 11, 2019

Model of the pulsed periodic discharge in Ar-S2 mixtures

Abstract

The kinetic (0-dimensional) model of a pulsed-periodic discharge in mixtures of argon with sulfur vapor, based on solution of the balance equations for plasma species and the electron energy balance equation was developed. The discharge is an effective source of radiation with spectrum, similar to solar spectrum in the wavelength range of 280-600 nm (B3Σ→X3Σ - transition of S2). Variation of plasma species densities during a voltage pulse for various Ar-S2 mixture compositions at different values of the reduced electric field (E/n) under gas pressure ~40 Torr was studied. It is shown, that a breaking field E/n, at which a transition from electronegative to electropositive plasma takes place, increases with sulfur fraction in Ar-S2 mixture. Ar-S2 plasma as simulations show is electronegative; the primary positive ions in Ar-S2 plasma are S2+ and Ar+ ions, the primary negative ions are S2- and S-ions. It is found that during the voltage pulse density of S2 * (B 3Σ ) molecules fast rises and exceeds densities of other excited species; however, when the voltage pulse decreases and, as a consequence, energy of electrons diminishes, density of excited sulfur molecules prompt falls while density of resonance excited argon atoms decreases very slowly. This is a reason for appearance of Ar lines along with S2 bands in spectra of the pulsed-periodic discharge in sulfur vapor argon mixtures.

Low-Pressure Plasma Processing and DiagnosticsAtmospheric-Pressure Plasma ApplicationsVacuum and Plasma Arcselectron energy balancereduced electric fieldplasma emission spectrum

Model of the pulsed periodic discharge in Ar-S2 mixtures

Abstract

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