Aimé MATHERON, UPX group, LOA: « Probing strong-field QED in beam-plasma interactions »

Recent progress in laser and accelerator technology opens new possibilities to investigate the largely unexplored strong-field quantum electrodynamics (SFQED) regime where electron-positron pairs can be created directly from light-vacuum fluctuations. When an electron beam impinges onto an overdense plasma, the beam self fields are reflected at the plasma surface which can result in a strong focusing effect for the beam. Passing through multiple thin plasma layers of solid density may allow to self-focus bunches with beam densities reaching the density of a solid and eventually probing the SFQED regime. This is the purpose of the E332 experiment at the SLAC National Accelerator Laboratory (Stanford) where this mechanism can be studied with unprecedented electron beam parameters available with the FACET-II accelerator facility. I will present the latest experimental results along with simulations of electron beam and plasma showing the focusing effect of the bunch and compare it to experimental data.