XXXIII International Conference on Plasma Physics and CF, February 13 – 17, 2006, Zvenigorod
NUMERICAL SIMULATIONS OF THE MICROWAVE DISCHARGE ON THE DIELECTRIC ANTENNA SURFACE
S.A. Dvinin, V.V. Mikheev, V.S. Sviridkina, V.M. Shibkov
Lomonosov Moscow State University, Physics department, Moscow, Russia,
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Microwave discharge on the boundary of dielectric antenna and gas created by a surface wave is considered in works [1-3]. It represents the self-conformed system as the dielectric waveguide is surrounded by plasma created by the surface wave, which is distributed along the waveguide. Experiments have shown, that such discharge can be realized in a wide range of surrounding gas pressure10-1-105 Pa. The discharge allows to support sizable plasma with essentially high charged particles concentration, because it can exist only when electron densities is higher, than critical one . Due to the specified properties this kind of the discharge can be applied for the most various problems – from low pressure plasma creation in technological reactors for microelectronics, to excitation of the discharge in high pressure gas that is typical for plasma-chemical reactors or plasma aerodynamics.
The discharge formation is experimentally investigated in [3], where it is shown, that plasma expansion process does not contradict to hypothesis of diffusive propagation mechanism [4]. Nevertheless, the relation between an electric field in a waveguide and one in plasma was not investigated in [3]; therefore the given statement requires the further check.
The models based on use of running waves approximation [5] cannot be directly applied to the description of a non-stationary problem, as they do not allow to describe correctly the field structure near to a transitive point from metal waveguide to plasma one and near to point of plasma abrupt, as they do not include processes of higher waveguide mode excitation. The given work is devoted to numerical simulation of the plasma generated in considered system.
The discharge is described by system of Maxwell equations and charged particles and electron energy balance equations. This system was solved numerically in bidimentional geometry. The received decisions contain also the higher modes of electromagnetic field, which amplitudes are essential, when plasma parameters change sharply. The non-reflection condition in infinity is achieved by using smoothly increasing field absorption far from discharge. The received decisions have allowed comparing values of an electric field in a waveguide and in plasma, including the areas of sharp changes of electron density.
Spatial distributions of electrons density and electromagnetic field spatial distributions in a vicinity of the dielectric antenna are obtained.
The received results on plasma density and dynamics of the discharge propagation are in the satisfactory consent with experiment [3].
References.
[1].Shibkov V.M., Vinogradov D.A., Voskanyan A.V. et al. MSU bulletin. Ser. 3, 2000, 41(6), 64.
[2].Shibkov V.M., Ershov A.P., Chernikov V.A., et al. Technical Physics, 2005, 75(4), 67.
[3].Shibkov V.M., Dvinin S.A., Ershov A.P., Shibkova L.V. Technical Physics, 2005, 75(4), 74.
[4].Dvinin S.A., Dovzhenko V.A. Fizika plasmy, 1988, 14, 66.
[5].Zakrzhewski Z., Moisan M. Plasma Sources Sci. Technol., 1995, 4, 379.
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