Effect of plasma temperature on electrostatic shock generation and ion acceleration by laser

The effect of plasma temperature on electrostatic shock generated by a circularly polarized laser pulse in overdense plasma is studied by particle-in-cell simulation. Ion reflection and transmission in the collisionless electrostatic shock (CES) are investigated analytically. As the initial ion temperature is varied, a distinct transition from the laser-driven piston scenario with all ions being reflected to the CES scenario with partial ion reflection is found. The results show that at low but finite temperatures the ions are much more accelerated than if they were cold.

Anomaly in photoelectron angular distributions

The recently observed anomaly in photoelectron angular distributions (PADs), the disappearance of the main lobes of PADs which should be usually in the direction of laser polarization, is reinterpreted as a minimum of generalized Bessel functions in the laser-polarization direction with the theory of nonperturbative quantum electrodynamics. The reinterpretation has no artificial fitting parameters and explains more features of the experimentally observed PADs, in contrast to the existing interpretation in which the anomaly is interpreted as a quantum interference of angular momentum partial waves. Some hierarchy anomalies are predicted for further experimental observations.

Bubble regime for ion acceleration in a laser-driven plasma

Proton trapping and acceleration by an electron bubble-channel structure in laser interaction with high-density plasma is investigated by using three-dimensional particle-in-cell simulations. It is shown that protons can be trapped, bunched, and efficiently accelerated for appropriate laser and plasma parameters, and the proton acceleration is enhanced if the plasma consists mainly of heavier ions such as tritium. The observed results are analyzed and discussed in terms of a one-dimensional analytical three-component-plasma wake model.

Acceleration of ultra-thin electron layer.Analytical treatment compared with 1D-PIC simulation

In this paper, we apply an analytical model [V.V. Kulagin et al., Phys. Plasmas 14, 113101 (2007)] to describe the acceleration of an ultra-thin electron layer by a schematic single-cycle laser pulse and compare with one-dimensional particle-in-cell (1D-PIC) simulations. This is in the context of creating a relativistic mirror for coherent backscattering and supplements two related papers in this EPJD volume. The model is shown to reproduce the 1D-PIC results almost quantitatively for the short time of a few laser periods sufficient for the backscattering of ultra-short probe pulses.