Gravitational Interaction of a Charge with a Cosmic String

Abstract

The gravitational interaction of a classical moving charge with an infinite straight cosmic string with linear energy density \(\mu\) is considered. The string generates a gravitational conical background with a small relative angular deficit \(\beta^{\prime}=4G\mu\). The geodesic of the charge lies in a plane transverse to the string. The scattering is described by the Lorentz factor \(\gamma\) and the impact parameter \(b\). In the leading order in \(\gamma\), the gravitational perturbation of the charge and the string is computed within the perturbation theory. In the second perturbation order, the total energy radiated in the form of electromagnetic waves is calculated, as well as the spectral–angular and polarization characteristics of the bremsstrahlung. The radiation is characterized by a concentration in a cone with opening angle of the order of \(1/\gamma\), with the dominant contribution to the emission coming from frequencies of the order of \(\gamma/b\).