Characteristic frequencies describing the rates of current decay in N-stran
d flat two-layer superconducting cables are studied. It is shown that these
frequencies when assembled in ascending order form N - 1 simple subspectra
. To each of these subspectra correspond characteristic currents possessing
a certain type of symmetry. For a uniform case, comparison of the characte
ristic currents with those generated by a time dependent magnetic field has
been performed.