  We demonstrate that charged particles in a sufficiently intense standing wave
are compressed toward, and oscillate synchronously at, the maxima of the
electric field. This unusual trapping behaviour, which we call 'anomalous
radiative trapping' (ART), opens up new possibilities for the generation of
radiation and particle beams, both of which are high-energy, directed and
collimated. ART also provides a mechanism for particle control in
high-intensity QED experiments.
