Charge density in a conducting medium revisited

In recent letters a dialogue on the classical dielectric relaxation time has taken place. We describe an extension of the usual derivation, based upon a more precise relationship between conduction current density and electric field intensity within a conductor. With this modification, the charge relaxes in a conducting medium with the classical dielectric relaxation time only if this time is much greater than the electron collision time . With metals where , the charge "relaxes" in an oscillatory manner typical of an underdamped second order system, with a relaxation time equal to and a frequency equal to the plasma frequency.