Beecroft Building, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU
Professor Chris Ridgers, University of York
Abstract
The laboratory realisation of dense, relativistic electron–positron plasmas is a major frontier in high-energy-density physics, essential for testing strong-field quantum electrodynamics (QED) and fir creating analogues of extreme astrophysical environments like pulsar magnetospheres. While current laser-driven schemes operate below the threshold of extreme QED cascades, next-generation multi-petawatt laser systems are poised to radically alter these interaction dynamics. In this work, we demonstrate that the mechanism of laser-driven relativistic electron–positron pair-jet production qualitatively changes as the laser intensity exceeds 5x10^22 W/cm^2). Above this threshold, an efficient channel opens to convert laser photons into dense pair-jets (>10^15/cm^3) via a combination of nonlinear inverse Compton scattering and the Bethe–Heitler process. At even higher intensities, the Compton-scattered photons become sufficiently energetic to cross the threshold for heavy-lepton creation, resulting in the prolific production of muons and anti-muons. This regime yields a unique, compact muon source with an extremely high peak flux (> 10^23/m^2/s), with potential application to future muon colliders, material radiography, and fundamental particle physics experiments.