Electron beam radiation by collective Compton boosting of strong turbulence

Several strong relativistic beam--plasma experiments have found powerful broadband microwave emission far above the plasma line. To model these experiments, consider scattering of electrons by cavitons of plasma turbulence of size D. This yields radiation Compton boosted to frequencies ∼2γ2c/D and relativistically beamed. To attain the observed powers (up to 108 W) the beam must be bunched. Several models for beam density fluctuation statistics can give the observed power, but only broad distributions, such as a Gaussian electrostatic spectrum in k, can yield a qualitatively wide radiation spectrum. Power scalings can be checked in future experiments