Longitudinal dielectric function and collective surface oscillations in superconductors

The electrodynamic approach to the problem of collective oscillations in superconductors is considered. The kinetic equation for quasiparticles is used to find the longitudinal dielectric function ₁(, k) of a pure superconductor at ( is the collision frequency). With the help of the evaluated ₁(, k) the existence of collective oscillations localized near the boundary of the superconductor is investigated.