The effects of electron energy distribution function on the plasma sheath structure in the presence of charged nanoparticles

摘要

The effects of the electron energy distribution function (EEDF) on the structure of a dusty plasma sheath are investigated. Here, it is assumed that the electrons obey a Druyvesteyn-type distribution with a parameter x controlling the shape of the EEDF. The Druyvesteyn-like distribution tends to a Maxwellian distribution as x varies from 2 to 1. Using the orbital motion limited theory, the incident electron current on the dust is evaluated for a given x. The results of numerical simulations are compared with those of a Maxwellian distribution. It was found that the sheath dynamics depends strongly on the magnitude of x. The sheath thickness increases monotonically with increasing x. However, the absolute dust charge decreases and, as a result, the accelerating ion drag force is weakened and thus the dust number density is enhanced. For a plasma with a Druyvesteyn-like distribution, the Bohm speed is a function of x and increases with increasing x.