  The radio/optical alignment effect for small powerful radio galaxies has been
shown to be produced by shock waves formed by the interaction of the head of
the jet and/or cocoon with clouds embedded in the interstellar/intergalactic
medium. We present here preliminary results of analytical and numerical
solutions that have been made to account for the production of implosive shock
waves induced by embedding cold clouds in the radio lobe of expanding powerful
radio sources.
