SCREENING OF STATIC ELECTROMAGNETIC-FIELDS IN HOT QED PLASMAS

We study the screening of static magnetic and electric fields in;massl ess quantum electrodynamics (QED) and massless scalar electrodynamics (SQED) at temperature T. Various exact relations for the static polari zation tenser are first reviewed and then verified perturbatively to f ifth order (in the coupling) in QED and fourth order in SQED, using di fferent resummation techniques. The magnetic and electric screening ma sses squared, as defined through the pole of the static propagators, a re also calculated to fifth order in QED and fourth order in SQED, and their gauge independence and renormalization-group invariance are che cked. Finally, we provide arguments for the absence of magnetic screen ing to an orders in perturbation theory.