Optimization of gas-filled quartz capillary discharge waveguide for high-energy laser wakefield acceleration

Abstract

A hydrogen-filled capillary discharge waveguide made of quartz is presented for high-energy laser wakefield acceleration (LWFA). The experimental parameters (discharge current and gas pressure) were optimized to mitigate ablation by a quantitative analysis of the ablation plasma density inside the hydrogen-filled quartz capillary. The ablation plasma density was obtained by combining a spectroscopic measurement method with a calibrated gas transducer. In order to obtain a controllable plasma density and mitigate the ablation as much as possible, the range of suitable parameters was investigated. The experimental results demonstrated that the ablation in the quartz capillary could be mitigated by increasing the gas pressure to ∼7.5–14.7 Torr and decreasing the discharge current to ∼70–100 A. These optimized parameters are promising for future high-energy LWFA experiments based on the quartz capillary discharge waveguide.