Gravitational waves in a spatially closed de Sitter spacetime

Perturbation of gravitational fields may be decomposed into scalar, vector and tensor components. In this paper we concern with the evolution of tensor mode perturbations in a spatially closed de Sitter background of Robertson-Walker form. It may be thought as gravitational waves in a classical description. The chosen background has the advantage of to be maximally extended and symmetric. Spatially flat models commonly emerge from inflationary scenarios are not completely extended. We first derive the general weak field equations. Then the form of the field equations in two special cases, planar and spherical waves, are obtained and their solutions are presented. The radiation field from an isolated source is calculated. We conclude with discussing the significance of the results and their implications.