Betatron oscillations in a free electron laser

Synchrotron-betatron parametric instability in free-electron lasers.

On electron betatron motion and electron injection in laser wakefield accelerators

We performed laser wakefield electron acceleration experiments using laser powers up to 100 TW in the ‘bubble’ regime. The measured angularly resolved energy spectra of the electron beam showed evidence of betatron oscillations during the acceleration process. Through diagnosis of these oscillations, electron injection into the wakefield could be controlled through adjustment of the shape of th...

Free Electron Laser in a Stripline Geometry

A thin dielectric slab over a conducting sheet is a low-loss slow-wave guiding system. When one introduces a magnetic wiggler into the system one may efficiently excite millimeter waves by passing a sheet electron beam just above the dielectric surface. For realistic parameters, the energy requirements on the beam are greatly reduced due to the wiggler. The frequency u, and the growth rate G ar...

Plasma Effects in a Free Electron Laser

The introduction of a plasma and a strong guide magnetic field in a free electron laser (FEL) slows down the phase velocity of radiation, significantly reducing the requirements on beam energy for generating frequencies below the electron-cyclotron frequency (oi, < oj,). Around plasma resonance (cu, ~ wp), the FEL mode couples to two-stream instability (TSI), attaining a large growth rate, comp...

Enhanced x-rays from resonant betatron oscillations in laser wakefield with external wigglers

Single photon counting techniques were used with an x-ray CCD camera to measure features of synchrotron-like x-ray spectra generated by betatron oscillations of electrons in a laser wakefield accelerator (LWFA) with different injection techniques. Measurements were made using the Hercules laser system at the University of Michigan. With a single stage gas cell, we demonstrate that pure helium g...