GRAVITATIONAL GEONS REVISITED

A careful analysis of the gravitational geon solution found by Brill a nd Hartle is made. The gravitational wave expansion they used is shown to be consistent and to result in a gauge-invariant wave equation. It also results in a gauge-invariant effective stress-energy tensor for the gravitational waves provided that a generalized definition of a ga uge transformation is used. To leading order this gauge transformation is the same as the usual one for gravitational waves. It is shown tha t the geon solution is a self-consistent solution to Einstein's equati ons and that, to leading order, the equations describing the geometry of the gravitational geon are identical to those derived by Wheeler fo r the electromagnetic geon. An appendix provides an existence proof fo r geon solutions to these equations. [S0556-2821(97)02220-0]. PACS num ber(s): 04.40.Nr, 04.20.Jb.