Gravitational back-reaction from colliding travelling waves on a cosmic string

• Main Author: Wells, R. Glenn
• Language: English
• Published: 2009
• Online Access: http://hdl.handle.net/2429/4939

In this thesis, I investigate the effects of the gravitational back-reaction force on two colliding triangular pulses travelling along an infinite cosmic string. The force is deter mined using a perturbative approach in the Lorentz gauge. This gauge choice is found to be reasonable in several aspects. Firstly, there is no gravitational back-reaction force on a single travelling wave. Secondly, the energy emitted by the string as gravitational radiation is the same as that lost by the string due to the back-reaction. Finally, the force can be made perpendicular to the string such that the perturbed string trajectory con tinues to satisfy the equations of motion. Unfortunately, the force equations contain an arbitrary gauge freedom making it difficult to form definite statements about the effects of the back-reaction force. However, choosing a reasonable value for the gauge parameter results in the two wave pulses being flattened out and having their sharp kinks rounded off.