2009/02/09 by Kazuhiko Kojima, Kiyotomo Ichiki, Kojima, Kazuhiko +1
Earth and Planetary Sciences · Physics and Astronomy · #Cosmology and Gravitation Theories #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #Geophysics and Gravity Measurements #Solar and Space Plasma Dynamics
paper · pdf · doi:10.48550/arxiv.0902.1367
openalex publication_date 2009/02/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Possible existence of the primordial magnetic fields has affected the structure formation of the universe. In this paper it is shown that the initial conditions for density perturbations with magnetic fields derived in previous works are inconsistent with Einstein equations. We find that this inconsistency arises due to the unwanted cancellation of contributions from the magnetic fields and primordial radiations. A complete set of equations and consistent initial conditions in the long wavelength limit are given with an explicit derivation in the covariant approach with CDM frame, by newly taking into account a non-relativistic matter contribution in the radiation dominated era. By solving these equations numerically, we derive the angular spectrum of cosmic microwave background anisotropies and the matter power spectrum with magnetic fields. We find that the amplitude of the angular power spectrum of CMB anisotropies can alter at most a order of magnitude at l \lesssim 4000 compared with the previous results in the literature.