Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

FULL ELECTROMAGNETIC FEL SIMULATION VIA THE LORENTZ-BOOSTED FRAME TRANSFORMATION

Conference ·
OSTI ID:991033
Numerical electromagnetic simulation of some systems containing charged particles with highly relativistic directed motion can by speeded up by orders of magnitude by choice of the proper Lorentz-boosted frame. A particularly good application for calculation in a boosted frame isthat of short wavelength free-electron lasers (FELs) where a high energy electron beam with small fractional energy spread interacts with a static magnetic undulator. In the optimal boost frame (i.e., the ponderomotive rest frame), the red-shifted FEL radiation and blue-shifted undulator field have identical wavelengths and the number of required longitudinal grid cells and time-steps for fully electromagnetic simulation (relative to the laboratory frame) decrease by factors of gamma^2 each. In theory, boosted frame EM codes permit direct study of FEL problems for which the eikonal approximation for propagation of the radiation field and wiggler-period-averaging for the particle-field interaction may be suspect. We have adapted the WARP code to apply this method to several electromagnetic FEL problems including spontaneous emission, strong exponential gain in a seeded, single pass amplifier configuration, and emission from e-beams in undulators with multiple harmonic components. WARP has a standard relativistic macroparticle mover and a fully 3-D electromagnetic field solver. We discuss our boosted frame results and compare with those obtained using the ?standard? eikonal FEL simulation approach.
Research Organization:
Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
Sponsoring Organization:
Accelerator& Fusion Research Division
DOE Contract Number:
AC02-05CH11231
OSTI ID:
991033
Report Number(s):
LBNL-3961E
Country of Publication:
United States
Language:
English