Topic/Type: 1.5 Low-temperature, dusty and nano-plasmas, Poster
Alexander Fedoseev1, Gennady Sukhinin1, 2
1 Institute of Thermophysics SB RAS, Novosibirsk, 630090, Russia
2 Novosibirsk State University, Novosibirsk, 630090, Russia
For a small Havnes parameter, , the charge of dust particles is determined only by the plasma conditions. With the increase of , the local parameters in the plasma region containing dust particles (the electron density and electron energy distribution function (EEDF)) change, which in turn leads to a change of the average charge of dust particles and, hence, of all properties of dusty plasma. For conditions of RF discharge used for thin films preparation in semiconductor industry, the influence of dust particles on discharge properties was investigated with the help of particle-in-cell Monte Carlo simulations by J.P. Boeuf [Phys. Rev. A, 46, 7910 (1992).]. It was understood that each dust particle acts as an electron and ion sink, and a large concentration of dust particles will have some effect on the plasma properties and on the plasma sustainment conditions. Unfortunately, in late 1990s and 2000s, this important conclusion was almost forgotten in avalanche-like investigations of dusty plasmas in the laboratory conditions (Coulomb structures, waves and so on). Moreover, in almost all papers published in this period in the field of dusty plasma, the electron energy distribution function in dusty plasma was assumed to be Maxwellian one.
For the charging of dust particles, the OML model with non-equilibrium EEDF was considered [G.I. Sukhinin, A.V. Fedoseev et al. J. Phys. D.: Appl. Phys., 40, 7761 (2007)]. The method of the solution of Boltzmann equation for EEDF was adopted for dusty plasma conditions, in which electron recombination on dust particles was regarded as volume recombination. These sub-models together with the neutrality condition were combined into a self-consistent kinetic model of a low pressure DC glow discharge with dust particles, which was solved numerically in an iterative way.
The influence of dust particles concentration, , on gas discharge parameters and the charging of dust particles were investigated. It is shown that the increase of leads to the increase of averaged electric field and ion density, and to the decrease of dust particle charge in the dusty cloud. The strong sink of electrons and ions on the dust particles surface does not lead to the electron energy distribution function depletion due to the self-consistent adjustment of dust particles and discharge parameters.
Financial support for this work was partly provided by RFBR Grant N 07-02-00781-a.