Progress on the study of direct laser electron acceleration in density-modulated plasma waveguides

Direct laser acceleration of electrons can be achieved by utilizing the axial field of a guided, radially polarized laser pulse in a density-modulated plasma waveguide. When a short fs electron bunch is injected together with the drive laser pulse, our particle-in-cell simulations show that the electrostatic field, arising from plasma electrons perturbed by the laser ponderomotive force, increases the transverse divergence of the bunch electrons. Simulations are performed to study the method in which a precursor electron bunch is introduced prior to the main accelerated bunch. The precursor induces a focusing electrostatic field in the background plasma, which can considerably reduce the transverse expansion of the accelerated electrons. Based on the ignitorheater scheme, density-modulated plasma waveguides are produced in experiments with high-Z gas targets and used to test the guiding of laser pulses. Supersonic gas jet nozzles for producing gas targets are simulated, designed, and then fabricated via additive manufacturing. Surface quality of the nozzles is evaluated via computed tomography.