Anisotropy of the electron component in a cylindrical magnetron discharge. II. Application to real magnetron discharge.

The physical processes occurring in electrode regions and the positive column of a cylindrical magnetron discharge in crossed electric and magnetic fields are investigated based on the solution of the Boltzmann kinetic equation by a multiterm decomposition of the electron phase space distribution function in terms of spherical tensors. The influence of the distribution function anisotropy on the absolute values and radial profiles of the electron density and rates of various transport and collision processes is analyzed. The spiral lines for the directed particle and energy transport are obtained to illustrate the anisotropy effects in dependence on the magnetic field.

Anisotropy of the electron component in a cylindrical magnetron discharge. I. Theory of the multiterm analysis.

A general multiterm representation of the phase space electron distribution function in terms of spherical tensors is used to solve the Boltzmann kinetic equation in crossed electric and magnetic fields. The problem is formulated for an axisymmetric cylindrical magnetron discharge with the homogeneous magnetic field being directed axially and the electric field between the coaxial cathode and anode varying in radius only. A spherical harmonic representation of the velocity distribution function in Cartesian coordinates becomes especially cumbersome in the presence of the magnetic field.

Two-dimensional nonlocal model of axially and radially inhomogeneous plasma of cylindrical magnetron discharge.

A cylindrical magnetron discharge (CMD) with two coaxial electrodes, a uniform axially directed magnetic field, and discharge ends closed by the shields biased at the cathode potential is considered. The presence of the shields creates axial inhomogeneity of plasma, which is taken into account in this study. At low pressures and small magnetic fields the pronounced nonlocal regime of the electron distribution function (EDF) formation is realized.

Nonlocal electron kinetics and excited state densities in a magnetron discharge in argon.

The densities of argon metastable (3)P(2), and resonance (1)P(1), (3)P(1) states were measured along a cylindrical magnetron discharge radius by absorption spectroscopy using a narrow bandwidth single mode diode laser. The theoretical treatment includes calculations of the rates of numerous excitation and decay processes based on nonlocal electron kinetics, and analysis of the transport equations for the resonance and metastable atoms. The solution technique of the Biberman-Holstein equation of radiation transport is developed in conformity with magnetron discharge geometry.

Kinetic simulation model of magnetron discharges.

A self-consistent kinetic model of plasma in the entire gap of a magnetron cylindrical discharge, with all quantities varying in radius and with the uniform magnetic field being directed axially, is presented. The discharge modeling is performed on the basis of a numerical solution of the spatially inhomogeneous Boltzmann kinetic equation together with equations of ion motion, current balance, and Poisson's equation. The model represents an example of discharge description from cathode to anode with respect to strong nonlocality effects in the distribution function formation.