Engineering topics

Breuer, R. A.

Publications and source records attributed to Breuer, R. A..

5 records

NASA NTRS1974

Gravitational Stokes parameters

The electromagnetic and gravitational Stokes parameters are defined in the general theory of relativity. The general-relativistic equation of radiative transfer for polarized radiation is then derived in terms of the Stokes parameters for both high-frequency electromagnetic and gravitational waves. The concept of Stokes parameters is generalized for the most general class of metric theories of gravity, where six (instead of two) independent states of polarization are present.

Anile, A. M.↗

NASA NTRS1973

Geodesic synchrotron radiation

This paper presents the results and methods of computing the high-frequency radiation emitted by freely falling particles moving in circular geodesic orbits in a spherically symmetric gravitational field. The high-frequency radiation, to which the methods of this paper apply, is the principal part of radiated energy only in the case of a particle moving in a highly relativistic, and therefore unstable, circular geodesic. The geodesic synchrotron radiation emitted in this case shows excitation of high-frequency harmonics and a narrow angular distribution. A Green's-function solution of the scalar wave equation is obtained using WKB methods. For application to relativistic circular orbits, a parabolic WKB approximation is required and yields solutions in terms of parabolic cylinder functions.

Breuer, R. A.↗

NASA NTRS1973

Vector and tensor radiation from Schwarzschild relativistic circular geodesics.

A technique developed by Regge and Wheeler (1957) is applied in the Schwarzschild background geometry to treat the radiation emitted by a test particle moving at a speed close to the local speed of light in the vicinity of a black hole. An analytic expression is obtained for the gravitational and electromagnetic radiation spectrum of a particle traveling in a highly relativistic orbit around a Schwarzschild blac hole.

Breuer, R. A.↗

NASA NTRS1973

Polarization of synchrotron radiation from relativistic Schwarzschild circular geodesics.

The pattern of geodesic synchrotron radiation emitted by a charge in an orbit close to the circular photon orbit at 3M around a nonrotating black hole of mass M is studied. The analysis is carried out using Stokes parameters, which completely characterize the state of the wave. The linear polarization, as observed at infinity, is total in the orbital plane and not smaller than 90% at the half-width of the beam. At the poles, pure circular polarization would be observed. In the region between the orbit plane and the poles the polarization shows features not present in ordinary synchrotron radiation. In our model, parameters more sensitive to deviations from the orbital plane are the Stokes parameter s (sub 2) and the tilt angle of the polarization ellipse.

Breuer, R. A.↗

NASA NTRS1972

Polarization of gravitational synchrotron radiation.

Development of a method of analysis of gravitational polarization in terms of Stokes parameters similar to those used for the electromagnetic case. Analytical expressions for these parameters are obtained for the gravitational synchrotron radiation corresponding to the Schwarzschild black-hole model. It is shown that interference between odd- and even-parity terms makes a significant contribution to the angular dependence of the polarization.

Breuer, R. A.↗