Surface-impedance of a metal with and without a magnetic field

The surface impedance for a metal with a cylindrical Fermi-surface is considered both in the presence of a magnetic field and without the magnetic field. The surface impedance is calculated both in the normal and in the anomalous skin-effect situation and a criterion for distinction between the two cases is given. This criterion is equivalent to a reinterpreted form of the one following from Pippard's ineffectiveness concept.