9:15 AM - 9:30 AM
[PEM17-14] Precursor Waves in Relativistic Shocks
Keywords:plasma, shock, particle acceleration
However, the efficiency of the particle acceleration by the wakefield mechanism is sensitive to the nature of the precursor electromagnetic waves, because the ponderomotive force is known to strongly depend on the wave amplitude and the wave coherence. In this study, we argue the precursor waves in relativistic shocks by using the two-dimensional PIC simulation. Since relativistic shocks are mainly controlled by “sigma parameter” which is the ratio of the Poynting flux and plasma flow energies, the amplitude of the precursor wave depends on sigma parameter. For instance, in our simulations, the amplitude of the precursor wave gets smaller and the wave coherency of the precursor wave gets lower as sigma parameter decreases, and the amplitude dependence on sigma parameter in two-dimensional simulations is different from that in one-dimensional simulations. Furthermore, the previous one-dimensional simulations could not investigate the wave coherency of the precursor wave. We must take account of the wave coherency when considering the wakefield acceleration because the wave coherency of the precursor wave, which is required for the ponderomotive force, is essential to the wakefield acceleration. In this presentation, we compare two-dimensional simulations to one-dimensional simulations and report our results.