Electron-cyclotron maser radiation from a relativistic loss-cone distribution

The electron-cyclotron maser instability is studied in a plasma with a loss-cone distribution for parameters relevant to tandem mirror devices. Both linear theory and particle simulations are employed. The effects of finite k/sub perpendicular/ are found to be very significant, and in general, the largest growth rate occurs for radiation emission perpendicular to the magnetic field. The instability persists at much lower densities (ω/sub p/e/Ω/sub e/ < 0.1) than indicated by previous analyses, which were limited to the case of parallel emission