  We present four new, high-resolution VLA radio images of the Crab nebula,
taken between 2001 Feb. and Apr. The radio images show systematic variability
in the Crab's radio emission throughout the region near the pulsar. The
principal geometry of the variable features is that of elliptical ripples very
similar to the optical wisps. The radio wisps are seen to move systematically
outward with projected speeds of up to 0.3c. Comparing the new radio images to
our earlier ones from 1998 and 2000, we show there are also more slowly moving
features somewhat farther away from the pulsar. In particular, there is a
prominent moving feature to the northwest of the pulsar which has a projected
speed of order 10,000 km/s. Striation is seen throughout the nebula, suggesting
the presence of wave-like disturbances propagating through the synchrotron
bubble. The radio images were taken simultaneously with HST optical
observations. Comparing the radio to the optical images, we find that the radio
wisps are sometimes displaced from the optical ones or have no optical
counterparts. We also find that some optical wisps in particular, the brightest
optical wisps near the pulsar, do not seem to have radio counterparts. In the
exterior of the nebula, by contrast, there is generally a good correspondence
between the radio and optical features.
