Improved hybrid Monte Carlo-fluid model for the electrical characteristics in an analytical radio-frequency glow discharge in argon

An improved hybrid Monte Carlo-fluid model for electrons, argon ions and fast argon atoms, is presented for the rf Grimm-type glow discharge. In this new approach, all electrons, including the large slow electron group in the bulk plasma, are treated with the Monte Carlo model. The calculation results presented here are the electrical characteristics (voltage, current and power as a function of time in the rf cycle, as well as the electrical potential and field distribution in the discharge), the electron and argon ion densities, and the electron, fast argon ion and atom impact ionization rates. In particular, the newly calculated electron impact ionization rate is more reliable now, because it is explicitly calculated in the electron Monte Carlo model instead of using an approximate formula, as in the earlier fluid model. Consequently, the major difference with our previous calculation results is found in the electron impact ionization rate. The calculated electrical characteristics (voltage, current and power) are, however, very similar to the results of our previous model. The new model confirms that the plasma displacement current is lower than the ion and electron conduction currents at the typical analytical rf Grimm-type glow discharge conditions, and therefore that the plasma current and voltage are in phase with each other. This is in contrast to other modeling results published recently, but in agreement with experimental observations where the capacitive current of the measuring circuit had also been subtracted from the total current.