Various definitions for the QCD Debye mass and its evaluation are reviewed in
a non-perturabtive framework for the study of screening of general static
sources. While it is possible to perturbatively integrate over scales ∼T
and thus construct a 3d effective theory, the softer scales ∼gT and ∼g2T are strongly coupled for temperatures \lsim 10^7 GeV and require
lattice simulations. Within the effective theory, a lattice treatment of
screening at finite quark densities \mu \lsim 4/T is also possible.Comment: 12 pages, 4 figures. Invited talk at Strong and Electroweak Matter,
Marseille, France, June 13-17, 200