Relativistic Laser-Plasma Physics

Abstract

This review covers recent progress in laser–matter interaction at intensities I above Irel 1⁄4 1:37 1018W=cm. At these intensities, electrons swing in the laser pulse with relativistic energies. The laser electric field is already much stronger than the atomic fields, and any material is instantaneously ionized creating plasma. The most important applications of relativistic laser-plasma include high-gradient acceleration of charged particles, new sources of short-wavelength, and nuclear radiation. The physics of relativistic laser-plasma is highly nonlinear and kinetic. The best numerical tools applicable here are particle-in-cell (PIC) codes, which exploit the fundamental plasma model as an ensemble of charged particles. The usage of massively parallel processing allows to follow simultaneously up to 10 numerical particles. This is enough to simulate directly real laser-plasma experiments even if the full-scale three-dimensional PIC simulations are expensive and parametric studies are difficult. In the ultrarelativistic limit I Irel, the Maxwell–Vlasov equations acquire a specific symmetry that leads to a very powerful analytical tool: the relativistic similarity theory. It allows to scale the interaction regimes and gives an important guide in the complex physics of relativistic laser-plasmas