  A microscopic theory of the magnetic-field modulation of critical currents is
developed for plane Josephson junctions with anharmonic current-phase
relations. The results obtained allow examining temperature-dependent
deviations of the modulation from the conventional interference pattern. For
tunneling through localized states in symmetric short junctions with a
pronounced anharmonic behavior, the deviations are obtained and shown to depend
on distribution of channel transparencies. For constant transparency the
deviations vanish not only near Tc, but also at T=0. If Dorokhov bimodal
distribution for transparency eigenvalues holds, the averaged deviation
increases with decreasing temperature and takes its maximum at T=0.
