Radially inhomogeneous electron kinetics in the DC column plasma

Abstract

The detailed radial structure of the electron kinetics in the positive column of cylindrical DC glow discharges is investigated to reveal the microscopic nature of the electron confinement by the radial space charge potential and the distinctly non-local properties of the kinetics. Therefore, a method has been developed to solve the relevant inhomogeneous kinetic equation including the radial electric field action and to determine the isotropic and anisotropic parts of the electron velocity distribution function. This allows one to determine the radial dependence of all important macroscopic quantities from the velocity distribution. Furthermore, the strict solution of the inhomogeneous equation can be used to inspect the validity of the so-called `non-local approach', which is a simpler kinetic model. The method is applied to a real neon glow discharge. Significant radial dependences of the isotropic distribution and, in particular, of the radial and axial anisotropic distributions were found with large consequences for the non-local behaviour of the electron particle and energy balance.