The Casimir surface force density on a compact material cylinder of ra
dius a is calculated, at zero temperature. A Green function approach i
s followed. The general theory is formulated so as to hold for arbitra
ry permittivities epsilon(omega) and permeabilities mu(omega), whereas
when it comes to explicit calculations the condition epsilon(omega) m
u(omega) = 1 is assumed to hold. A simple dispersion relation is chose
n, implying a high frequency cutoff omega0. The theory yet diverges, a
t high angular momenta. Divergences of this sort usually appear whenev
er there are curved boundaries present. On physical grounds an angular
momentum cutoff mo can be introduced, being of order omega0a. A semi-
quantitative calculation of the force thereby becomes possible. The ca
lculated force is attractive. (C) 1994 Academic Press, Inc.