Microwave discharges produced by surface waves in argon gas

Abstract

This paper reports on an experiment in argon discharges produced by surface waves at 2.45 GHz. A self-consistent description of these discharges at low pressure ( p < 10 Torr) is presented. Characteristics such as the electron density, the maintaining electric field (E), the collision frequency for momentum transfer Y and the mean power required for maintaining the electron-ion pair 8 are determined as functions of the product of the pressure and the plasma diameter. In particular, scaling laws are verified for v and 8. It is concluded that experimental surface-wave discharges behave similarly to positive-column discharges.

Activation energy of an asymmetrical, radio frequency discharge with methane

“…Results supporting this assumption were obtained by Meichsner et al and Riccardi et al [28,29]. Moreover, the situation is similar to surfacewave-produced microwave and positive-column discharges [27,30]. Hence, the expansion of the active plasma zone is approximated by a linearly falling curve starting at the point of maximum intensity thus that the net intensity, i.e., the integral below the measured curve, is maintained (Fig.…”

“…Therefore, it is assumed that the plasma intensity falls linearly with the distance from the electrode, which is caused by the finding that the plasma density falls almost linearly when a constant axial electric field is present [27]. Results supporting this assumption were obtained by Meichsner et al and Riccardi et al [28,29].…”

Travelling-wave-sustained discharges

“…They involve measurements of the wave characteristics (wavenumber and its variation along the discharge length) for determination of the plasma parameters (plasma density and its axial profile) by using knowledge for the wave dispersion properties. The interferogram method and the field radial decay method are the radiophysics methods [4,65,76,[121][122][123][124][125][126][127][128] first invented, the former-the interferogram method-has been very widely used in the diagnostics of the SWSDs. A lot of results [4,5,65,76,[121][122][123][124][125][126][127][128] have been accumulated, by using this method, for the axial density profile-the most remarkable characteristic of the SWSDs, which is a consequence of the self-consistent interdependence between the parameters of the guided wave and of the generated plasma.…”

“…These are the so-called "radiophysics" methods [4,5,13,15,65,76,[121][122][123][124][125][126][127][128] which provide results for plasma characteristics from measurements of the wave propagation properties. Among these methods, the interferogram method has been widely used for accumulating results for the axial profiles of plasma densityn(z).…”

A microwave discharge source operating at pressures of several atmospheres

“…The advantage of such devices is that it is possible to produce a stable plasma in them at pressures of up to several atmospheres, since, in this case, drawbacks related to problems of sustaining an HF or microwave discharge at elevated pressures in resonance sources are eliminated. Characteristics of the discharge initiated by the surface wave were intensively studied for plasma of Ar [11]; He [12]; O 2 [13,14] ; N 2 [15]; He, Ne, and Ar [16]; H 2 [17,18]; and é 2 -N 2 [19] ; and Ar-N 2 mixtures [20,21]. The discharge structure of the surfatron consists of two coaxially placed metallic cylinders forming a section of the coaxial line short-circuited on one end by a plunger and having an circular gap on the other end.…”