Gravitational radiation from electromagnetic systems

The spectrum of the gravitational radiation emitted by a charge e with mass m undergoing a finite motion in an electromagnetic field which varies smoothly around the orbit over the range of its radius of curvature, is shown to differ, in the ultrarelativistic limit, from the spectrum of the charge's electromagnetic radiation only by the coefficient 4piGm-squared(Gamma-squared)/e-squared, which is independent of the frequency. Here Gamma is of the order of magnitude of the Lorentz factor of the charge and depends on the direction of the wave vector and on the behavior of the field in the region indicated. In a plane-wave external field the gravitational and electromagnetic spectra are strictly proportional to each other for arbitrary charge velocities. Localization of external forces near the orbit violates the proportionality of the spectra and weakens the gravitational radiation in order of magnitude as the square of the Lorentz factor.