  Low -frequency dynamic impedance
($\sigma^{-1}(\omega,T)\equiv(\sigma_{1}+i\sigma_{2})^{-1}$) measurements on
Josephson junction arrays with finite vortex screening length $\xi$, found that
$\sigma_{1}\sim |\log{\omega}|$, $\sigma_{2}\sim$ constant. This implies
anomalously sluggish vortex mobilities $\mu_{V}(\omega)\sim\sigma_{1}^{-1}$,
and is in conflict with general dynamical scaling expressions that yield, for
low-$\omega$, $\sigma_{1}\rightarrow\xi^{2}$ and $\sigma_{2}\rightarrow 0$. We
calculate : a) $\sigma(\omega,T)$ by real-space vortex scaling; b)
$\mu_{V}(\omega)$ using Mori's formalism for a screened Coulomb gas. We find,
in addition to the usual critical (large-$\omega$) and hydrodynamic
(low-$\omega$) regimes, a new intermediate-frequency scaling regime into which
the experimental data fall. This resolves the above mentioned conflict and
makes explicit predictions for the scaling form of $\sigma(\omega,T)$, testable
in SNS and SIS arrays.
