Gravitational perturbations in plasmas and cosmology
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Gravitational perturbations can be in the form of scalars, vectors or tensors. This thesis focuses on the evolution of scalar perturbations in cosmology, and interactions between tensor perturbations, in the form of gravitational waves, and plasma waves.
The gravitational waves studied in this thesis are assumed to have small amplitudes and wavelengths much shorter than the background length scale, allowing for the assumption of a flat background metric. Interactions between gravitational waves and plasmas are described by the Einstein-Maxwell-Vlasov, or the Einstein-Maxwell-fluid equations, depending on the level of detail required. Using such models, linear wave excitation of various waves by gravitational waves in astrophysical plasmas are studied, with a focus on resonance effects. Furthermore, the influence of strong magnetic field quantum electrodynamics, leading to detuning of the gravitational wave-electromagnetic wave resonances, is considered. Various nonlinear phenomena, including parametric excitation and wave steepening are also studied in different astrophysical settings.
In cosmology the evolution of gravitational perturbations are of interest in processes such as structure formation and generation of large scale magnetic fields. Here, the growth of density perturbations in Kantowski-Sachs cosmologies with positive cosmological constant is studied.
Place, publisher, year, edition, pages
Umeå: Institutionen för Fysik , 2010. , 48 p.
general relativity, cosmology, gravitational waves, plasma, electromagnetic waves, nonlinear waves
Fusion, Plasma and Space Physics Other Physics Topics Astronomy, Astrophysics and Cosmology
Research subject Theoretical Physics
IdentifiersURN: urn:nbn:se:umu:diva-38387ISBN: 978-91-7459-125-5OAI: oai:DiVA.org:umu-38387DiVA: diva2:376489
2011-01-04, Naturvetarhuset, N430, Umeå Universitet, Umeå, 13:00 (English)
Clarkson, Christopher, Dr.
Brodin, Gert, Prof.Bradley, Michael, Prof.
List of papers