Reflection and absorption of a p-polarised wave by a metal with a nonuniform electron temperature

The complex reflection coefficient of a p-polarised wave incident on a metal with electrons nonuniformly heated over the depth is found under the conditions of a high-frequency skin effect. The derived expressions for the absorption coefficient and the phase shift of a reflected wave are applicable in the case of an arbitrary ratio of the penetration depth of radiation to the spatial scale of the inhomogeneity of small contributions to the dielectric constant, which are caused by electron collisions. It is shown that the use of Fresnel formulae is not always possible and can lead to significant errors if the temperature of hot electrons changes at the skin-layer scale.