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DOI:10.18429/JACoW-FEL2015-TUP008
Title High-Gain FEL in the Space-Charge Dominated Raman Limit
Authors
  • I.I. Gadjev, C. Emma, A. Nause, J.B. Rosenzweig
    UCLA, Los Angeles, USA
Abstract While FEL technology has reached the EUV and X-ray regime at existing machines such as LCLS and SACLA, the scale of these projects is often impractical for research and industrial applications. Sub-millimeter period undulators can reduce the size of a high-gain EUV FEL, but will impose stringent conditions on the electron beam. In particular, a high-gain EUV FEL based on undulators with a sub-millimeter 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 space-charge effects to the foreground of the FEL process. When the wavelength of plasma oscillations in the electron beam becomes comparable to the gain-length, the 1D theoretical FEL model transitions from the Compton to the Raman limit. In this work, we investigate the behavior of the FEL's gain-length and efficiency in these two limits. The starting point for the analysis was the one-dimensional FEL theory including space-charge forces. The derived results were compared to numerical results of Genesis 1.3 simulations. This theoretical model predicts that in the Raman limit, the gain-length scales as the beam current to the -1/4th power while the efficiency plateaus to a constant.
Paper download TUP008.PDF [0.465 MB / 4 pages]
Conference FEL2015, Daejeon, Republic of Korea
Series International Free Electron Laser Conference (37th)
Proceedings Link to full FEL2015 Proccedings
Session Poster Session
Date 25-Aug-15   15:00–17:00
Main Classification FEL Theory
Keywords FEL, space-charge, undulator, electron, simulation
Publisher JACoW, Geneva, Switzerland
Editors Heung-Sik Kang (PAL, Pohang, Republic of Korea); Dong Eon Kim (PAL, Pohang, Republic of Korea); Volker RW Schaa (GSI, Darmstadt, Germany);
ISBN 978-3-95450-134-2
Published December 2015
Copyright
Copyright © 2015 by JACoW, Geneva, Switzerland     CC-BY Creative Commons License
cc Creative Commons Attribution 3.0