On properties of QED plasmas

Current advances in laser-plasma and astrophysical observations of magnetar emission demand better understanding of how quantum electrodynamics (QED) effects that are present in strong-field environments affect plasma dynamics. Interestingly, astrophysical systems such as extremely strongly magnetized neutrons stars, called `magnetars' possess magnetic fields far in excess of the Schwinger (critical) field, so these effects can no longer be ignored. In particular, Maxwell's equations become nonlinear in the strong-QED regime. This effect has not, so far, been incorporated in plasma codes; systemic theoretical studies of QED-plasmas are also absent. Here we present the derivation of the general equation of linear plasma modes in QED-plasma with arbitrarily strong magnetic field. We discuss general trends and some properties of the low-frequency modes. These results can be of interest for understanding of electron-positron plasma in a magnetar magnetosphere, as well as future lab experiments.