The effects of temporal pulse shape on laser wakefield accelerators: preliminary results

It is generally assumed that the most desirable laser pulse for laser wakefield accelerators (LWFA) is one that is Fourier transform limited (FTL). Such a pulse minimizes the duration of the pulse, thus maximizing the pulse peak intensity, and creates a pulse shape that is symmetric in the time domain. However, recent studies have shown that laser pulses that are carefully shaped in the temporal regime can significantly enhance the resultant radiation of LWFA, such as increasing the maximum energy of photons by 50% [1] or the electron beam charge by 80% [2]. To further our understanding of the interaction between the pulse shape and laser driven plasmas, the recently developed direct phase control (DPC) method [3] for pulse shaping was used in conjunction with particle-in-cell (PIC) simulations of LWFA. This presentation will briefly address how the DPC pulse shaping method works before focusing on preliminary results of the PIC simulations and the possible physical mechanisms that explain the enhancements seen from the pulse shaping.