Decoherence in a chirped-pulsed free-electron maser

Conference · Thu Jul 01 04:00:00 EDT 1999

OSTI ID:20067604

Hartemann, F V; Landahl, E C; Troha, A L; Heritage, J P; Baldis, H A; Luhmann, Jr, N C

Theoretical studies have shown that the relativistic subpicosecond electron bunches produced by high-brightness rf photoinjectors can be used to generate coherent synchrotron, radiation in a free-electron maser (FEM). Furthermore, in a waveguide structure, the group velocity in the helical wiggler, thus minimizing slippage in the device and yielding extremely short pulse of coherent millimeter-wave radiation, with instantaneous bandwidths exceeding 50%. Because of group velocity dispersion, the output pulses are chirped. The transition from coherent to incoherent synchrotron radiation in the FEM has first been studied within the context of a relativistic fluid model; the authors will discuss the limitations of such a model, and propose a new hybrid model capable of describing the electron bunch behavior both in the electron fluid and stochastic gas limits. In particular, there is a continuous transition from the exponential coherence factor of the fluid model, to the incoherent radiation scaling, N{sub e}. This will be discussed both in the context of fast-wave FEMs, and for short wavelength, laser-driven Compton scattering sources.

• Research Organization: Lawrence Livermore National Lab., CA (US)
• Sponsoring Organization: US Department of Energy; US Department of Defense
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 20067604
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
COHERENT RADIATION
ELECTRON BEAMS
FREE ELECTRON LASERS
MASERS
MATHEMATICAL MODELS
SYNCHROTRON RADIATION
WIGGLER MAGNETS