Self-gravitating cosmic rings

The classical Einstein-Maxwell field equations admit static horizonless wor mhole solutions with only a circular cosmic string singularity. We show how to extend these static solutions to exact rotating asymptotically flat sol utions. For a suitable range of parameter values, these solutions describe charged or neutral rotating closed cosmic strings, with a perimeter of the order of their Schwarzschild radius. (C) 1999 Published by Elsevier Science B.V. All rights reserved.