HOLLOW SPHERE AS A DETECTOR OF GRAVITATIONAL-RADIATION

The most important features of the proposed spherical gravitational wa ve detectors are closely linked with their symmetry. Hollow spheres sh are this property with solid ones, considered in the literature so far , and constitute an interesting alternative for the realization of an omnidirectional gravitational wave detector. In this paper we address the problem of how a hollow elastic sphere interacts with an incoming gravitational wave and find an analytical solution for its normal mode spectrum and response, as well as for its energy absorption cross sec tions. It appears that this shape can be designed having relatively lo w resonance frequencies (similar to 200 Hz) yet keeping a large cross section, so its frequency range overlaps with the projected large inte rferometers. We also apply the obtained results to discuss the perform ance of a hollow sphere as a detector for a variety of gravitational w ave signals. [S0556-2821(97)00522-5].