PIC Modeling Of Collisional Skin Depth In RF-Driven Atmospheric Pressure Plasmas

Atmospheric pressure plasmas have application in plasma processing and plasma lighting. One common technique for creating these plasmas is to use RF to drive a discharge in a gas column. A main unexplained feature of these discharges is a radial contraction of the plasma, believed to depend in part on the depth to which the RF wave penetrates the gas column. We present collisional particle-in-cell (PIC) simulations of such a system, specifically looking at how the collisions modify the plasma skin depth for these parameters and geometries. We find the skin depth changes roughly 30% from 0.53 mm to 0.71 mm as the temperature increases from 0 to 500 eV for parameters relevant to atmospheric pressure plasmas in use today.