Detailed Spectra of High-Power Broadband Microwave Emission from Intense Electron-Beam-Plasma Interactions

Abstract

For a relativistic electron beam penetrating an unmagnetized plasma, a change is seen in the emission spectrum from $\ensuremath{\omega}\ensuremath{\sim}{\ensuremath{\omega}}_{p}$, $2{\ensuremath{\omega}}_{p}$ line emission to continuous $\ensuremath{\omega}\ensuremath{\gg}{\ensuremath{\omega}}_{p}$ emission, as $\frac{{n}_{b}}{{n}_{p}}\ensuremath{\rightarrow}1$. High-power (of order megawatts per gigahertz) broadband radiation up to \ensuremath{\sim}100 GHz suggests collective Compton-boosting mechanisms in a new regime of superstrong turbulence. Highly directional emission and magnetic field dependence agree with this interpretation.