Self-Modulated Laser Wakefield Acceleration as an Electron Source for High Energy Density Science

Relativistic electron beams have many useful applications in high energy density science including x-ray generation, and positron generation. Laser wakefield accelerators offer a compact means of generating high energy low divergence electron beams to be used for these applications. In the self-modulated regime of laser wakefield acceleration, the laser pulse is many times longer than the plasma period, generating multiple bubbles to trap and accelerate electrons. The Titan laser at the Jupiter Laser Facility produces a Self-modulated laser wakefield accelerator (SM-LWFA) using a 120 J, 1 ps, 1 um laser pulse focused at an intensity of ~10¹⁹ W/cm² onto a He gas jet with an electron density of about 5*10¹⁸ cm^-3. This SMLWFA produces an electron beam of 10 nC with a maximum energy of 300 MeV and a divergence of 50x100 mrad. This work will present the electron beam properties as a function of laser and plasma parameters in experiments at the Titan laser.