Exploring electron beam and radiation generation using femtosecond and picosecond laser pulses

The interaction of an intense laser pulse with an underdense plasma will expel electrons, giving rise to electron density oscillations. Through this process, electrons can be accelerated to significant energies, beyond the ponderomotive limit. For pulse durations less than the plasma period, the dominant electron acceleration mechanism is Laser Wakefield Acceleration (LWFA). However, for longer pulse durations the transverse laser field becomes the dominant acceleration mechanism, giving electrons longitudinal momentum via the v x B force. This is known as Direct Laser Acceleration. In my talk, I will discuss the generation of high energy electron beams and ultrafast radiation sources using picosecond and femtosecond laser pulses. Experiments on the OMEGA EP laser facility have demonstrated acceleration of electrons up to a record 0.6 GeV using a high-energy, picosecond pulse at an optimal plasma density. 2D Particle-In-Cell simulations confirm DLA as the dominant mechanism and elucidate the role of quasi-static fields on acceleration. Additionally, LWFA studies conducted using the HERCULES laser system at the University of Michigan and the Rutherford Appleton Laboratory explore the generation of mid-infrared radiation in this regime and the high-resolution imaging capabilities of LWFA X-ray sources.