(TH-1-04) Presenting Author: J. H. Brownell
J.E. Walsh, J.H. Brownell, J. Swartz, S. Trotz; M. Kimmitt; G. Doucas; R. Fernow, H. Kirk, V. Yakimenko
Dept. of Physics and Astronomy, Dartmouth College, Hanover, NH 03755; University of Essex; University of Oxford; Brookhaven National Laboratory
In the first investigations of radiation produced by electrons skimming over the surface of a diffraction grating, Smith and Purcell [Phys. Rev., 92, 1069, 1953] employed an electron beam of a few hundred kilo-volts and a few micro-amperes. Subsequent work was typically carried out with beams of comparable or lower energy. Investigations of grating coupled radiation with relativistic electron beams have begun only recently. To date, the primary focus has been on the structure of the uncorrelated emission from individual electrons or emission from electron bunches with length less than the emitted wavelength. In the latter case, the total energy emitted can exceed that of the former case by many orders of magnitude though it remains a spontaneous or shot noise process. In contrast with the relativistic case, coherent emission produced by low energy electron beams moving over a grating has been observed in a number of experiments. It is of fundamental interest to assess the prospects for coherent grating induced emission (SASE) from relativistic beams. A review of recent progress in relativistic beam-grating experiments and a summary of the current status of SASE theory will be presented.
