Fluid simulations of glow discharges: Effect of metastable atoms in argon

Abstract

A one-dimensional fluid simulation of a 13.56 MHz argon glow discharge including metastable species was performed as an example of a coupled glow-discharge/neutral-transport-reaction system. Due to the slow response time of metastables ( -10 ms) direct time integration of the coupled system requires -lo5 rf cycles to converge. This translates to prohibitively long computation time. An "acceleration" scheme was employed using the Newton-Raphson method to speed up convergence, thereby reducing the computation time by orders of magnitude. For a pressure of 1 Torr, metastables were found to play a major role in the discharge despite the fact that their mole fraction was less than 10V5. In particular, metastable (two-step) ionization was the main mechanism for electron production to sustain the discharge. Bulk electric field and electron energy were lower, and a smaller fraction of power was dissipated in the bulk plasma when compared to the case without metastables. These results suggest that neutral transport and reaction must be considered in a self-consistent manner in glow discharge simulations, even in noble gas discharges. 3668

Ion chemistry in H2-Ar low temperature plasmas

“…Other reactions of excited Ar, such as the reaction Ar m + Ar m → Ar + + Ar + e − , are not relevant for our plasma conditions due to the low pressure. However, for pressures higher than 1 Pa this reaction cannot be neglected 48,49 . For the wall loss of Ar m Eqn.…”

Влияние Температуры На Ионизационный Коэффициент И Напряжение Зажигания Таунсендовского Разряда В Смеси Аргона С Парами Ртути

“…Разрядный промежуток, а также интер-валы изменения v и v z разбивались на 100 частичных интервалов, т. е. s = 100. При расчете переноса ионов и метастабилей в смеси вследствие малого содержания в ней ртути использовались значения подвижностей в аргоне атомарных и молекулярных ионов аргона и ртути из [27,28,40], а также значения коэффициентов диффузии в аргоне метастабильных атомов обоих газов, приведенные в [28,32].…”

Heat flux into the substrate and electric power measurement in radio frequency discharge plasma

“…Here, D a represents the ambipolar diffusion coefficient, and is given by Here, N g D i = 2.07 × 10 18 cm -1 s -1 is used for the argon ion diffusion coefficient D i , and the ion temperature T i is assumed to be 300 K [5]. N g is the gas molecule density.…”