Acceleration of a young supernova remnant by an associated pulsar

We present a numerical model of the action of a pulsar on its associated su pernova remnant. The expansion of the blast wave in the progenitor star has first been considered until radiation pressure within the ejected material becomes negligible due to expansion. By assuming that expansion is ballist ic and that the ejecta is opaque to the pulsar 's magnetodipole radiation, the model produces a radiation-filled cavity which grows around the pulsar and contributes to power the dynamics of the forming supernova remnant. The interface between the cavity and the ejecta has been modelled as a thin sh ell which, depending on the initial spin frequency of the pulsar, can sweep through the ejecta and reach the blast wave. Results for the evolution of the shell indicate that it may strike the frontmost part of the shocked gas some 60 years after the explosion. Such pulsar-supernova remnant interacti ons are proposed to form the base of a new subclassification of pulsar-fill ed supernova remnants.