Optical injection in a laser wake field accelerator

Summary form only given. Monoenergetic beam production in Laser-Plasma based accelerators requires a high quality relativistic plasma wave which will remain synchronized with accelerated electrons and produce a uniform acceleration. Optically generated injection-electrons have the advantage of being tightly bunched and synchronized to the laser wakefield for phased injection and acceleration to final high energies. Large number of injected electrons can be generated using a combination of LIPA (Laser Ionization and Ponderomotive Acceleration) and SM-LWFA (Self Modulated LWFA). These electrons are generated by the interaction of a 10 TW laser beam of the NRL T/sup 3/ laser with a gas jet of high density nitrogen. Electrons energy and angular distributions were studied experimentally and numerically. The number, energy distribution and pulse length of the electrons make it good candidate for phased injection. Injection of these electrons into a second stage of acceleration operating in the standard LWFA regime can lead to further acceleration. The wake field in the second stage acceleration is generated in helium gas using a 2 TW laser beam of the NRL T/sup 3/ laser. Setup and results of the experiments will be presented.