Spontaneous spin-polarisation of plasmas and their emission of highly polarised gamma-ray pulses in strong electromagnetic fields

The behaviour of matter in strong electromagnetic fields is a fundamental area of physics. As electromagnetic fields approach the so called 'Sauter-Schwinger' field our basic theories describing this behaviour no longer work and a new state of matter - a quantum electrodynamic (QED)-plasma - is created. Here the electric field in the rest frame of the plasma electrons approaches the Sauter-Schwinger field and strong-field QED effects play a dominant role in the dynamics of this 'QED-plasma'. QED-plasmas are expected to determine the interaction of upcoming multi-PW lasers with matter and so the viability of transformative applications of these lasers ranging from novel imaging techniques to proton therapy. QED-plasmas are also found in extreme astrophysical environments, such as the magnetospheres of pulsars, magnetars and active black holes. Until very recently, however, there has been no model which captures all of the important quantum effects, severely limiting our ability to model QED-plasmas. In particular we have demonstrated that the intrinsic angular momentum of high-energy particles, namely electron/positron spin and gamma-ray photon polarisation are very important. In this project we will include our ground-breaking new model, which includes both spin and gamma-ray polarisation, in the plasma modelling code EPOCH and using this to fully explore their affect on QED-plasmas for the first time.