VI Int. Workshop on Microwave Discharges: Fundamentals and Applications
September 11-15, 2006, Zvenigorod, RUSSIA
modelling of a nonequilibrium spherical electric discharge Under higher modes of incident microwaves
I.R. Rafatov
Middle East Technical University, TR-06531 Ankara, Turkey
This work deals with the modelling of a nonequilibrium spherical microwave discharge.
Self-consistent model of a thermal and ionization nonequilibrium spherical microwave discharge, which takes into account the first spherical mode of the incident electromagnetic waves, has been constructed in [1]. The aim of the present work is the numerical investigation of the effect of the higher modes on the nonequilibrium spherical microwave discharge characteristics.
It is assumed that the axial symmetric electric discharge is taking place inside a spherical chamber with a dielectric wall and is sustained by the microwave power of convergent electromagnetic waves. The model is constructed on the basis of a two-temperature approximation of the plasma [2]. The discharge is described by the system of Maxwell’s equations, the energy balance equations for each species of plasma, and the equations for the structure of the plasma, which consist of the continuity equation for electrons, the condition of quasineutrality, the equations of state and Dalton’s law.
Numerical experiments are carried out for the discharge in an argon at atmospheric pressure. Results are presented for the characteristics of the discharge plasma against the external parameters: the mode, frequency and power of the applied electromagnetic field and the size of the discharge chamber.
Calculations show that at rather small microwave frequencies, effect of the higher modes is insignificant. At larger frequencies, their effect becomes comparable with the effect of the first mode. Effect of the higher modes dependent on the size of the discharge chamber is qualitatively similar.
References
1. Rafatov I.R. and Lelevkin V.M. J. Phys. D: Appl. Phys., 2005, 38 2227
2. Lelevkin V.M., Otorbaev D.K. and Shram D.C. Physics of Non-Equilibrium Plasmas. Amsterdam: North-Holland, 1992