|
abstract:
|
A high-gain free-electron laser is modeled using an expansion of the radiation field in terms of guided
Laguerre-Gaussian modes of a virtual dielectric waveguide E. Hemsing, A. Gover, and J. Rosenzweig, preceding
paper, Phys Rev. A 77, 063830 2008 . The radiation profile evolution, power gain, and detuning
efficiency characteristics are investigated for seeding with fundamental Gaussian and higher-order Laguerre-
Gaussian input modes on a Gaussian e-beam in the collective regime. The full wave evolution solution at
different seed radiation injection conditions results in determination of the optimal waist size and waist position
of the seed radiation beam for maximum power coupling efficiency. Results for guided mode evolution and
power gain are shown to be consistent with simulations performed with the code GENESIS 1.3. The amplification
and spontaneous generation of FEL radiation with orbital angular momentum is also considered.
|