  We study the quantum and thermal fluctuations of eddy (Foucault) currents in
thick metallic plates. A Casimir interaction between two plates arises from the
coupling via quasi-static magnetic fields. As a function of distance, the
relevant eddy current modes cross over from a quantum to a thermal regime.
These modes alone reproduce previously discussed thermal anomalies of the
electromagnetic Casimir interaction between good conductors. In particular,
they provide a physical picture for the Casimir entropy whose nonzero value at
zero temperature arises from a correlated, glassy state.
