Propagation of surface waves in two-plasma systems bounded by a metallic enclosure

Abstract

This paper examines the possibility of propagating surface waves in cylindrical plasma–plasma structures enclosed by metal walls and submitted or not to a static magnetic field. We consider the situation in which the inner plasma layer is overdense while the other is underdense. It is shown that outside the electron cyclotron resonance (ECR) conditions, the outer plasma layer plays a role similar to that of an ordinary dielectric layer, just modifying the wavenumber without drastically changing the general characteristics of the wave. At ECR, a major change in the wavenumber and attenuation coefficient is observed, a cutoff occurring on the left side of ECR and a resonance on the right side, provided the outer plasma density is large enough. It is further found that in conditions where the outer plasma layer thickness is very small, wave propagation still occurs, whatever the density value in this region. This suggests that surface wave propagation is possible in plasma–sheath–metal structures.