Abstract
Laser-driven relativistic electrons in plasma channels emit short-wavelength continuum radiation into a narrow solid angle along the beam axis. Electron acceleration and radiation emission are analyzed in terms of a single-electron model of direct laser acceleration. An analytical solution for radiation pulses emitted from the turning points of resonantly excited electron oscillations in the channel is presented. The total radiated power and the width of the power spectrum show an ∼ I1.4 scaling with the laser intensity I.