2006/04/11 by Joachim Moortgat, M. Marklund, Mattias Marklund
Physics and Astronomy · #Black Holes and Theoretical Physics #Classical mechanics #Cosmology and Gravitation Theories #Covariant transformation #Galaxies: Formation, Evolution, Phenomena #General relativity #Gravitation #Isotropy #Long wavelength limit #Mathematical physics #Perturbation (astronomy) #Physics #Plasma #Quantum electrodynamics #Quantum mechanics #Wavelength #astro-ph #gr-qc
paper · pdf · doi:10.1111/j.1365-2966.2006.10419.x
published as Mon.Not.Roy.Astron.Soc.369:1813-1821,2006 · 9 pages. Accepted for publication in MNRAS, 5 April 2006 (submitted 20 Januari 2006)
arxiv created 2006/04/11 · openalex publication_date 2006/05/18 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We study the properties of density perturbations of a two-component plasma with a temperature difference on a homogeneous and isotropic background. For this purpose, we extend the general relativistic gauge-invariant and covariant (GIC) perturbation theory to include a multifluid with a particular equation of state (ideal gas) and imperfect fluid terms due to the relative energy flux between the two species. We derive closed sets of GIC vector and subsequently scalar evolution equations. We then investigate solutions in different regimes of interest. In particular, we study long-wavelength and arbitrary-wavelength Langmuir and ion-acoustic perturbations. The harmonic oscillations are superposed on a Jeans-type instability. We find a generalized Jeans criterion for collapse in a two-temperature plasma, which states that the species with the largest sound velocity determines the Jeans wavelength. Furthermore, we find that within the limit for gravitational collapse, initial perturbations in either the total density or charge density lead to a growth in the initial temperature difference. These results are relevant for the basic understanding of the evolution of inhomogeneities in cosmological models.