High-frequency behavior of layered superconductors with Josephson coupling

Electrodynamic behavior of a layered system with Josephson couplings between layers is considered. It is shown that in the case of slow spatial variations of fields along layers all electrodynamics of the system can be reduced to a set of equations describing evolution of Josephson phases. In a more general case, applicable to high-{ital T}{sub {ital c}} materials, one cannot reduce description to phases, but needs to consider electromagnetic fields in the system. Such consideration leads to modified, time-dependent London equations, different for longitudinal and transverse fields. Low-lying, nondecaying waves are analyzed for a layered structure. It is shown that the surface impedance is essentially affected by these waves. In systems with large anisotropy excitations of internal waves lead to strong transverse losses appearing at comparatively low frequencies. {copyright} {ital 1996 The American Physical Society.}