  We investigate the magnetic response of normal-metal--superconductor
proximity systems for arbitrary concentrations of impurities and at arbitrary
temperatures. Using the quasiclassical theory a general linear-response formula
is derived which yields a non-local current-field relation in terms of the
zero-field Green's functions. Various regimes between clean-limit and (local)
dirty-limit response are investigated by analytical methods and by solving the
general formula numerically. In the ballistic regime we find that a finite mean
free path reduces the non-locality and leads to a stronger screening than in
the clean limit even for a mean free path much larger than the system size.
Additionally, the range of the kernel describing the non-locality is strongly
temperature-dependent in this case. In the diffusive limit we find a cross-over
from local to non-local screening, which restricts the applicability of the
dirty-limit theory.
