Stimulated emission from relativistic electrons passing through a spatially periodic longitudinal magnetic field

Abstract

Stimulated emission in the high gain regime from a cold, relativistic beam of electrons gyrating in a combined solenoidal and longitudinally polarized, periodic, wiggler magnetic field is considered as a source of short wavelength radiation. The emitted wave frequency is Doppler upshifted in proportion to the wavenumber of the wiggler magnetic field. Amplification is due to a ponderomotive bunching force acting on the electrons in the transverse and axial directions. Expressions for the linear growth rate are obtained; conditions for their validity, and estimates for the saturated efficiency are given.

Spontaneous emission in longitudinal wiggler and solenoidal magnetic field

“…A preliminary analysis [21] shows that the energy spread requirements for the longitudinal wiggler are somewhat less stringent than the conventional helical undulator field. Also not included in the analysis are the electron betatron oscillations due to finite radial inhomogeneity of the longitudinal wiggler.…”

A high-efficiency free-electron laser-peniotron hybrid with a longitudinal wiggler magnetic field

“…The lowbitron is also a hybrid system of the free-electron laser and the cyclotron, in which a beam of electrons gyrating in a combined solenoidal and longitudinally polarized periodic wiggler magnetic field interacts with the cyclotron electromagnetic mode to generate stimulated radiation. 2 These two devices have a common characteristic, that is they work at the same beam line Ϫ( c ϩk w v ʈ )Ϫk ʈ v ʈ Ϸ0, and therefore work at the same high frequency. They have another common characteristic, that is their efficiencies are low, typically a few percent.…”