Type D gravitational fields

by Kinnersley, William Morris

Abstract (Summary)
The Newman-Penrose tetrad equations are set up for the principal tetrad of a Type D gravitational field in vacuum. With no further assumptions, the equations are integrated, yielding an exhaustive list of Type D vacuum metrics. The solutions all possess two commuting Killing vectors and depend on from one to four arbitrary constants. The Type D fields with expanding rays are six closely related versions of Kerr-NUT space, the EhlersKundt "C" metric, and a new generalization of the "C" metric possessing rotation. For zero expansion we find the three EhlersKundt "B" metrics, plus rotating generalizations of each. The six Kerr-NUT metrics are interpreted as spinning particles with timelike, lightlike, or spacelike momentum and angular momentum vectors occurring in all possible combinations. The "C" metric is tentatively identified as a gravitational analog of the runaway solutions encountered in electrodynamics, i. e. , a point mass executing hyperbolic motion. Next we consider Type D fields with electromagnetism present. We find that all of the above vacuum metrics can be readily "charged" by adding a non-null electromagnetic field whose principal null vectors coincide with the gravitational ones. We also discuss some interesting generalizations of the Schwarzschild and "C" metrics containing the geometrical optics limit of a null electromagnetic field which propagates along one principal null congruence. In the Schwarzschild case they generalize Vaidya's "shining star" metric, to include the field of a particle traveling along an arbitrarily accelerated world-line.
Bibliographical Information:

Advisor:Jon Mathews

School:California Institute of Technology

School Location:USA - California

Source Type:Master's Thesis



Date of Publication:07/08/1968

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