Laser-based discharge ignition for capillary waveguides

Highly energetic electron beams are required for various applications such as free-electron lasers and particle colliders. Nowadays these beams are almost exclusively produced in conventional radiofrequency-cavities, which are limited to typical acceleration gradients below 50 MV/m. Hence long machines on the order of 100 m are required to reach the desired energies. Laser-wakefield accelerators in plasma on the other hand are capable of providing acceleration gradients well above 10 GV/m, thereby allowing for much more compact devices on scales of centimeters. Currently, plasma-based devices are rapidly evolving and improving, but still suffer from instabilities in the generated electron-beam properties, largely due to shot-to-shot variations of laser and plasma parameters. In order to minimize possible sources for these fluctuations, a novel, more stable technique for shaping the transverse plasma-density profile in a plasma accelerator based on laser triggering and ignition of capillary discharge waveguides is presented.