Optimization of a Laser Plasma Accelerator through Pulse Characterization and Controlled Spatiotemporal Coupling
Unlike conventional accelerators, the accelerating structure in a laser plasma accelerator (LPA) is dynamically created by the interaction of a high-peak-power laser pulse with a plasma target. This dynamic nature allows extensive control over the acceleration process but requires detailed knowledge and regulation of the laser, the plasma target, and their interaction. In this thesis, the effect of laser pulse structure, in particular temporal profile and spatiotemporal coupling, on laser plasma acceleration is investigated through theoretical models and experiments at the BErkeley Laboratory Laser Accelerator (BELLA) Center. The temporal profile of the laser and the density profile of the plasma target are probed by laser spectral shifting. A novel model of laser steering and electron beam deflection due to pulse front tilt is developed. The effects of pulse front tilt are measured in experiments and found to be in good agreement with the theoretical model. The application of these results for the optimization of a laser plasma accelerator is discussed.