Experimental Opportunities for the Ion Channel Laser

Abstract

The ion channel laser (ICL) was originally proposed as a compact, plasma-based alternative to the free electron laser (FEL) [1]. It is, in many ways, analogous to the FEL, though it offers some distinct advantages all on its own. Most notably, the ICL can accommodate a larger electron energy spread, making it better suited for high-brightness plasma-injected beams. In addition, the same radiator (plasma source) can be used to produce elliptically polarized light without alteration, a feature that is absent in an FEL. Historically, electron beam quality and plasma source development were insufficient for the demonstration of the ICL. In addition, the ICL appeared unfavorable due to the inherently short Rayleigh length of the radiation it produced. Recent literature, however, has shown that high gain can be achieved, despite the short Rayleigh length [2]. In addition, current and near-future facilities are able to provide appropriate beams and plasma sources for the ICL. Experimental opportunities to demonstrate an ICL at the Facility for Advanced Accelerator Experimental Tests II (FACET-II) are presented, utilizing both a 10 GeV beam originating from the SLAC National Accelerator Laboratory linac, and a 1 GeV high-brightness, plasma-injected beam.