Effects of magnetic wiggler field and chirped laser pulse on the wakefield amplitude and electron energy gain in a wiggler-assisted laser wakefield accelerator

Abstract

Wakefield generation and GeV electron acceleration in a plasma medium by an ultra-short and intense chirped laser pulse in the presence of a magnetic wiggler field are presented. To increase the wakefield amplitude and to maximize the acceleration gradient, we employ a helical magnetostatic wiggler. An analytical theory of wakefield generation and electron energy gain has been presented which includes the effects of the wiggler field. It was found that the wakefield spectrum and electron energy gain in the wiggler-assisted wakefield accelerator can be increased significantly compared to the non-wiggler situation ones. Numerical simulations reveal that for moderate wiggler magnetic field strengths, wakefield amplitude and electron energy gain have significant peaks in bubble-like structures. Besides, when the wiggler wavelength is clearly larger than the plasma wavelength, the wakefield amplitude and electron energy gain significantly enhance. In addition, it was found that the electron bunches can be enhanced by increasing the wiggler field strength or wiggler wavelength. The effect of the laser chirp parameter on wakefield and electron energy gain have also been investigated. It was concluded that in a wiggler-assisted laser wakefield accelerator, the electron energy and wakefield evolution can be tuned by the wiggler field strength, wiggler wavelength, and laser chirp parameter. This concept opens a path toward new generation of plasma accelerators based on wiggler structures.