Producing Extreme Light Intensities with Relativistic Plasma Mirrors

Multi-petawatt laser facilities, such as Apollon in Paris, will generate very high light intensities to explore novel strong-field frontiers in plasma- and laboratory astrophysics. Relativistic plasma mirrors represent a promising technology to significantly boost the peak laser intensity by utilizing highly nonlinear light-plasma interactions that happen at the mirror surface. The objective of my research is to numerically simulate these laser-plasma interactions to understand how they impact the maximum laser intensities that can be achieved. The results of my simulations will support the experimental campaign at Apollon and could also be relevant for the future science program at FACET-II (SLAC). At both facilities researchers aim to reach the QED critical (Schwinger) field, where modern quantum field theories predict a qualitative change: at this scale the electric field is strong enough to efficiently ``ionize the vacuum'', i.e. to permanently separate electron-positron pairs that exist as virtual quantum fluctuations everywhere in space. This will allow us to study exotic phenomena otherwise only encountered in cosmic laboratories such as neutron stars or black holes.