Charging kinetics of dust particles in a non-Maxwellian Lorentzian plasma

Abstract

Charging kinetics of uniformly dispersed spherical dust particles in a non-Maxwellian plasma, characterized by a Lorentzian (κ) distribution function of electrons/ions has been developed; the formulation is based on the uniform potential theory, applicable to the dust particles characterized by a size distribution function. Owing the openness character of the complex plasmas, the charging kinetics has been developed on the basis of number and energy balance of the plasma constituents along with the charge balance over the dust particles; the neutrality of the complex plasma is a consequence of the number balance of electrons/ions and charge balance on the dust particles. A more rigorous approach, proposed by Mott-Smith and Langmuir [Phys. Rev. 28, 727 (1926)] has been adopted to derive the expressions for the electron/ion accretion current over the dust surface and corresponding mean energy in a non-Maxwellian Lorentzian plasma. Further the formulation has been implemented to determine the secondary electron emission (SEE) from the spherical dust particles in such plasmas. The departure of the results for the Lorentzian plasma, from that in the case of Maxwellian plasma has been graphically illustrated and discussed. It is seen that the Lorentzian nature of the plasma and the inclusion of the collective effect of the dust particles significantly affects the dust charge and other plasma parameters; the formulation and understanding of the charging kinetics in a Lorentzian plasma have implications for both the physics (e.g. grain growth and disruption) and the dynamics of dust in laboratory and space environment, when the dimension of the plasma are much larger than the diffusion length.