Аннотация

The effect of the nonequilibrium state of an electron gas on sound absorption in a superconductor is considered. The nonequilibrium electron distribution function is assumed to be stationary and isotropic, and the phonons to be in equilibrium. In addition to the explicit dependence of the damping coefficient on the distribution function, a dependence on the correction to the order parameter exists that is associated with the nonequilibrium state. The sound intensities which create the nonequilibrium state and at which nonlinearity should be observed are estimated.