[en] It is common knowledge that a wave is totally reflected from the surface of a collisionless plasma whose frequency, ωsub(p), exceeds that of the incident light ω. If the electromagnetic wave is powerful enough (the radiation pressure exceeds the kinetic pressure of the plasma), this phenomenon can be used for plasma confinement or acceleration. The paper demonstrates that when the plasma is confined by the pressure of a linearly polarized electromagnetic wave, the collisionless layer manifests signs of resistive behaviour; this phenomenon is associated with longitudinal plasma oscillations excited by the pulsing component of the Lorentz force. The formal cause of these resistive effects is resonance at the point where ωsub(p)=2ω; this point appers when ωsub(p) inside the layer changes from zero to values exceeding 2ω