KINETIC-THEORY FOR A DISTRIBUTION OF IONIZED DUST PARTICLES

Dust particles, assumed to be of one size and to exhibit a discrete di stribution of electric charges, are treated as heavy ions with a large number of ionization levels. The average of the discrete particle eff ects on the kinetic equations is approximated by the Lenard-Balescu co llision term and by detailed counting to describe transport in velocit y space and transitions between the different ionization levels respec tively. We estimate analytically and numerically the relaxation times for the dust particles both towards a Maxwellian velocity distribution and towards an equilibrium distribution for the ionization levels. We sum over the ionization levels to obtain a hierarchy of 'charge-momen t' equations for the single dust density function, and estimate the im portance of terms originating from the ionization distribution. Simila r terms are also present in the hydrodynamic equations for a dust plas ma, and we briefly discuss these.