MODELING OF A PLASMA-COLUMN PRODUCED AND SUSTAINED BY A TRAVELING ELECTROMAGNETIC-WAVE IN THE PRESENCE OF A CONSTANT AXIAL MAGNETIC-FIELD

We present the basic equations for modeling a plasma column produced and sustained by a traveling electromagnetic wave in the presence of a constant external magnetic field. The model consists of two equations-a local-dispersion relationship and a wave-energy-balance equation-and a relation between the absorbed wave power per unit length averaged across the column (proportional to the squared-wave electric field) and the local electron number density. The dispersion relation and the balance equation are derived in explicit forms and depend on two numerical parameters sigma = omega-R/c (omega being the wave angular frequency, R the plasma column radius, c speed of light) and OMEGA = omega-c/omega (omega-c is the electron cyclotron frequency). The limit of an infinite external magnetic field (OMEGA --> infinity) is also considered. The influence of the two parameters OMEGA and sigma on the dimensionless axial profiles of the wave characteristics and plasma column density, obtained by numerical solution of the basic equations, has been studied for two different gas-discharge regimes. A three-dimensional wave structure has been obtained, and it is shown that the wave can be a generalized surface mode, a pure surface, or a pseudosurface one. The results obtained are in agreement with the available experimental data.