Possibility of generating a high-power self-similar radiation pulse from a free-electron laser.

Abstract

Using 1D short-wavelength (8 \ensuremath{\mu}m) Compton free-electron-laser (FEL) equations with slippage, we explore propagation of a high-power pulse down a tapered undulator FEL traveling-wave amplifier. For an appropriate taper, a short pulse (\ensuremath{\sim}300 fsec FWHM) with regular features will propagate self-similarly as it grows in power, slipping through a much longer electron pulse. The power spectrum of the pulse is nearly Gaussian with no sidebands. The electron energy is depressed by \ensuremath{\sim}33%, but slippage causes the peak pulse intensity to be about the same as the electron-beam power density, \ensuremath{\sim}10 TW/${\mathrm{cm}}^{2}$.