PURE AND GRAVITATIONAL-RADIATION

The well known treatment of asymptotically flat vacuum fields is adapt ed to pure radiation fields. In this approach we find a natural normal ization of the radiation null vector. The energy balance at null infin ity shows that the mass loss results from a linear superposition of th e pure and the gravitational radiation parts. By transformation to Bon di-Sachs coordinates the Kinnersley photon rocket is found to be the o nly axisymmetric Robinson-Trautman pure radiation solution without gra vitational radiation.