Null-brane solutions in supergravities

We find a new class of time-dependent brane solutions in supergravities in arbitrary dimensions D. These are general intersecting light-like branes (null-branes), and their superposition and intersection rules are obtained. This is achieved by directly solving bosonic field equations for supergravity coupled to a dilaton and antisymmetric tensor fields. We discuss their possible significance. (C) 2003 Published by Elsevier Science B.V.