Comparison Between Induced Compton Scattering Experiments and Particle-In-Cell Simulation

Induced Compton scattering (CS) is a quantum nonlinear interaction between an intense electromagnetic field and a rarefied plasma. Although the induced CS is expected to occur in radiation fields with high brightness temperatures such as pulsars in nature, the principle of induced CS has not been proven experimentally. Therefore, we conducted a proof-of-principle experiment of induced CS using an ultra-intense laser. We measured the scattered spectra due to the interaction between the ultra-intense laser and plasma. The observed spectrum shows a nonlinear redshift, which can be explained by induced CS. We also performed particle-in-cell simulations, in which induced CS is not included, and found that the experimental results are not explained by classical plasma physics.