Meter-Scale Supersonic Gas Jets for Multi-GeV Laser-Plasma Accelerators

Pushing the high energy frontier of laser wakefield electron acceleration to 10 GeV and beyond requires extending the propagation of relativistic intensity pulses to ∼1 m in a low density (Ne ∼ 10¹⁷ cm^-3) plasma waveguide. We present the development and characterization of two types of supersonic gas jets for meter-scale multi-GeV laser wakefield accelerators. The first type is a 30-cm long single-module gas jet, which demonstrates good axial uniformity using hydrogen. The second type is a modular jet composed of multiple 11-cm-long modules. Longitudinal density profile control is demonstrated with a 2-module (22 cm long) hydrogen jet using gas valve trigger timing. A 1.0-m-long jet is then assembled from nine modules, and generation of 1.0-m long hydrogen plasma is demonstrated using a femtosecond Bessel beam. To our knowledge, this is the longest gas jet laser plasma yet generated.