We calculate the order of magnitude of the emission rate of electromagnetic waves, and of massive scalar particles, from oscillating vacuum strings and domain walls. The energy loss due to electromagnetic radiation is shown to be much smaller than that due to gravitational radiation. Scalar radiation can only damp oscillations of frequency of the order of the scalar particle mass. Our results confirm the assumption made in previous work that gravitational radiation is the dominant energy-loss mechanism for macroscopic vacuum structures.

• Received 9 May 1984

DOI:https://doi.org/10.1103/PhysRevD.30.2046