The electromagnetic response of a mesoscopic cylinder made of a normal
metal or a semiconductor is studied. The relation between the induced
current J(q, w) and the electric field E(q, w) is derived. It is shown that the
kernel K(q, w) which determines the properties of the system has a finite
limit which implies infinite conductivity. The mesoscopic cylinder by virtue
of its topology and small dimensions can support a persistent current. If the
coherence of currents from different channels is strong enough a novel effect
— the self-sustaining current can be obtained. We show tlat a mesoscopic
multichannel system exhibits some features which bear resemblance to the
superconductor
