Interaction of an electromagnetic wave with a suddenly stopped ionization front

The theory of the interaction of an electromagnetic wave with a uniformly moving ionization front in a gas is extended to include the case when the front suddenly stops. This nonstationary character of the wave/front interaction, which is typical for experiments carried out in a finite-size gas tube, gives rise to new effects. First, free-streaming currents induced near the plasma boundary after the front stops produce a static magnetic field not only in the plasma behind the front but also in vacuum ahead of the front. Second, in the regime when the transmitted wave falls off behind the front, the skinning field leaks through the stopped front and produces a burst of highly frequency upshifted radiation.