LANL, Los Alamos, New Mexico
NPS, Monterey, California
SAIC, McLean
LANL, Los Alamos, New Mexico
SAIC, McLean
* H. P. Freund, S. G. Biedron, and S. V. Milton, IEEE J. Quantum Electron. 36, 275 (2000)
| Paper | Title | Page |
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| THAAU03 | A Scalloped Electron Beam Free-Electron Laser | 509 |
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| Typical high-gain FEL amplifiers employ an electron beam that is matched to the wiggler so that the envelope remains constant throughout the wiggler. This paper describes a novel approach in which the electrons undergo natural betatron scalloping motion along the wiggler because the beams are deliberately mismatched at the wiggler entrance. We present an analysis of the electron scalloping motion and the FEL interaction with a scalloped electron beam. For a representative set of beam and wiggler parameters, we discuss the effect of the pinching the electron beams on the interaction in the FEL and on the focusing and propagation of the FEL radiation. | ||
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| THBAU04 | Stair-Step Tapered Wiggler for High-Efficiency FEL | 545 |
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A new concept of a high-efficiency wiggler called the stair-step tapered wiggler is presented. The stair-step tapered wiggler differs from the traditional continuously tapered wigglers in that there are several uniform wiggler segments with decreasing wiggler periods (or decreasing Krms). Thanks to the relatively large ponderomotive potential in each segment, a substantial fraction of the electrons is captured while the electrons execute synchrotron motion down the energy scale. This leads to high FEL extraction efficiencies and partial optical guiding in the tapered wiggler sections. The stair-step tapered wiggler provides other advantages, such as ease of fabrication and flexibility in the taper rate. Numerical simulations using the code MEDUDA* will be presented to show the high-efficiency performance of a representative FEL with a stair-step tapered wiggler.
* H. P. Freund, S. G. Biedron, and S. V. Milton, IEEE J. Quantum Electron. 36, 275 (2000) |
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