Self-similar imploding relativistic shock waves
  Self-similar solutions to the problem of a strong imploding relativistic shock wave are calculated. These solutions represent the relativistic generalisation of the Newtonian Gouderley-Landau-Stanyukovich problem of a strong imploding spherical shock wave converging to a centre. The solutions are found assuming that the pre-shocked flow has a uniform density, and are accurate for sufficiently large times after the formation of the shock wave. 
J.C. Hidalgo, S. Mendoza