Transition Between Beam-Plasma and Beam-Dissipative Instability Regimes in the Interaction of Relativistic Large Larmor Orbit Electron Beams and Azimuthal Surface Waves Above the Upper-Hybrid Frequency in Coaxial Plasma Waveguides

Abstract

Azimuthal surface waves are eigen-electromagnetic waves which propagate in coaxial plasma-vacuum waveguides across an axial stationary magnetic field. Their excitation in the coaxial plasma layer by the flow of electrons which rotate along large Larmor orbits either around or inside the plasma layer has been well studied in the collision-less approach. The influence of weak collisions between the plasma particles on the growth rate of such waves for both cases of the electron beam placement is studied here for the frequency range above the upper-hybrid frequency and compared to the case of the electron cyclotron frequency range. Transition from the regime of beam-plasma instability to that of a beam-dissipative instability is discussed.