Minisymposium Presentation

To answer the needs of modelling strong field interaction, PIC codes require tailored additional development. In particular, we have incorporated additional physics such that in-house developed OSIRIS framework could be used to simulate plasmas in extreme conditions, from the classical to the fully QED-dominated interaction. OSIRIS-QED module has an embedded Monte Carlo algorithm to account for quantum processes, which has been thoroughly benchmarked against known analytical results, codes used in the particle physics community (e.g. GUINEA-PIG). Besides physics developments, simulating the extreme regime has particular challenges on memory, load balance and temporal discretization, which required particular code developments oriented towards performance. We have developed Macro-particle merging algorithm and tailored load balance techniques to address the exponentially rising number of particles in QED cascades. This was followed by semi-analytical particle pusher development for better accuracy and coupling the OSIRIS Quasi-3D geometry with OSIRIS-QED module. More recent developments of my team include the Bethe-Heitler pair production and cross-section evaluation based on Machine Learning. All these developments are aimed to incorporate new physics while minimizing impact on performance and scalability.