Pure-radiation gravitational fields with a simple twist and a Killing vector - art. no. 064011

Pure-radiation solutions are found exploiting the analogy with the Euler-Da rboux equation for aligned colliding plane waves and the Euler-Tricomi equt ion in hydrodynamics of two-dimensional how. They do not depend on one of t he spacelike coordinates and comprise the Hauser solution as a special subc ase.