Topic/Type: 2.3 Hybrid methods, including PIC/DSMC and PIC/Fluid, Invited

Simulation of radiation dominated regimes in ultra-intense laser fields with a particle code

H. Ruhl, N. Elkina

Ludwig-Maximilians-University, Munich, Germany

With the advent of new, powerful laser facilities like ELI classical and quantum radiation dominated regimes are entered. In the past efforts have been undertaken to incorporate classically radiating electrons into simulation codes. Those efforts have been based on the Lorentz-Abraham-Dirac (LAD) equations, which, however, appear to be unsatisfactory to many authors. At larger laser field strengths the classical realm of radiation is left and quantum electrodynamical processes have to be considered. A possible quantum scenario are successive events of electron-positron pair production accompanied by the emission of hard radiation in the presence of strong external laser fields and energetic particles as has been proposed recently. At the largest field strengths conceivable within the next decade or so self-induced QED cascades might become observable. Hence, classical and quantum radiation processes must be taken seriously in future simulation codes for high-field laser-matter or laser-vacuum interaction.

We will report about the progress we have achieved with designing a simulation code for classical and quantum radiation processes in the presence of ultra-strong laser radiation. In the classical realm we will discuss the implementation of Caldirola-like equations into a simulation code and their limitations for the simulation of classical radiation. In the quantum realm we will review transport equation formulations, probability rates and geometries of elementary QED processes, discuss Monte-Carlo schemes for calculating rates, and show how we have implemented them into a simulation code. The numerical costs for useful simulations of radiation dominated regimes will be estimated. First results will be shown.