Paper 
Title 
Page 
TUP008 
HighGain FEL in the SpaceCharge Dominated Raman Limit 
347 

 I.I. Gadjev, C. Emma, A. Nause, J.B. Rosenzweig
UCLA, Los Angeles, California, USA



While FEL technology has reached the EUV and Xray regime at existing machines such as LCLS and SACLA, the scale of these projects is often impractical for research and industrial applications. Submillimeter period undulators can reduce the size of a highgain EUV FEL, but will impose stringent conditions on the electron beam. In particular, a highgain EUV FEL based on undulators with a submillimeter period will require electron beam currents upwards of 1 kA at energies below 100 MeV. Coupled with the small gap of such undulators and their low undulator strengths, K < 0.1, these beam parameters bring longitudinal spacecharge effects to the foreground of the FEL process. When the wavelength of plasma oscillations in the electron beam becomes comparable to the gainlength, the 1D theoretical FEL model transitions from the Compton to the Raman limit. In this work, we investigate the behavior of the FEL's gainlength and efficiency in these two limits. The starting point for the analysis was the onedimensional FEL theory including spacecharge forces. The derived results were compared to numerical results of Genesis 1.3 simulations. This theoretical model predicts that in the Raman limit, the gainlength scales as the beam current to the 1/4th power while the efficiency plateaus to a constant.


Export • 
reference for this paper to
※ LaTeX,
※ Text,
※ IS/RefMan,
※ EndNote (xml)


