| The new generation of laser systems such as ELI (Extreme Light Infrastructure) will produce laser intensities as high as 10^W/cm^. New physical processes need to be considered under theses conditions. For intensities higher than 10²² W/cm², the radiation losses may have strong effects on the dynamics of the laser-matter interaction. In order to describe this process, we have implemented radiation back reaction [1] in the equation of motion of charged particles in the 3D relativistic Particle-In-Cell (PIC) code, PICLS [2]. We assume that particle motion is ultrarelativistic implying a computational advantage. Furthermore, radiation of each charged particles is independent and incoherent due to small wavelenght of radiation compared to average distance between charged particles. The limits of this model will be discussed and applications of our model will be presented. First example concerns collisionless shock dynamics in gamma ray burst. The expanding layers or jets of an exploding star interact with the interstellar medium, creating a collisionless shock. Strong heating of electrons in the shock front lead to generation of a broad and electromagnetic radiation and particle acceleration. Recent numerical simulations on it show that ions accelerated at the shock front might play a signifiant role in the shock evolution, in particular in the injection of ions in the acceleration phase [3]. Heating of electrons might be affected by the radiation losses. Another example is related to the role of radiation effects on ion acceleration and heating of electrons in the context of laser-plasma interaction. This process involves the interaction of laser field with electrons in the shock front. We focus on modeling energy spectrum of emitted photons. These studies are complementary and provide a link between laser-matter interaction and shocks dynamics in astrophysics. |
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