Eigenmodes in an ultra-relativistic ultra-magnetized pair QED-plasma

Ultra-relativistic quantum-electrodynamic (QED) plasmas, characterized by magnetic field strengths approaching and exceeding the Schwinger field of approximately BQ≈4×1013 gauss, hold significant interest for laser–plasma experiments and astrophysical observations of neutron stars and magnetars. A previous study developed the QED-plasma framework for analyzing collective plasma phenomena for arbitrarily strong magnetic fields, especially in the ultra-magnetized super-Schwinger-field regime. In that study, QED modifications to plasma normal modes characterized by the linear regime in a cold plasma have been explored. In the current study, we extend the previous analysis to investigate the joint modification of normal plasma modes in ultra-relativistic electron–positron plasmas, both charge-neutral and non-neutral, by the superstrong magnetic field and plasma relativistic temperature. Our analysis shows that the most substantial modification concerns the reduction of the plasma frequency cutoff, resulting in relativistic and field-induced transparency. Additionally, we observe a temperature-independent modification of the index of refraction of electromagnetic waves, which coincides with the behavior observed in a cold QED plasma.