Resistive Generation of Intergalactic Magnetic Field at Cosmic Dawn
Miniati & Bell (2011) proposed a mechanism for the generation of magnetic seeds that is based the finite resistivity of the low temperature IGM in the high redshift universe. In this model, cosmic-ray protons generated by the first generation of galaxies, escape into the intergalactic medium carrying an electric current that induces return currents, jt, and associated electric fields, E = ηjt there. Because the resistivity, η, depends on the IGM temperature, which is highly inhomogeneous due to adiabatic contraction and shocks produced by structure formation, a non-vanishing curl of the electric field exists which sustains the growth of magnetic field. In this contribution we have developed an approximate numerical model for this process by implementing the source terms of the resistive mechanism in the cosmological code CHARM. Our numerical estimates substantiate the earlier analysis in Miniati & Bell (2011) which found magnetic seeds between 10-18 and 10-16 Gauss throughout cosmic space at redshift z ∼ 6, consistent with conservative estimates of magnetic fields in voids at z ∼ 0 from recent gamma-ray experiments.
Numerical Modeling of Space Plasma Slows (ASTRONUM 2011)
- Pub Date:
- July 2012
- Astrophysics - Cosmology and Extragalactic Astrophysics;
- Astrophysics - High Energy Astrophysical Phenomena
- 6 pages, 2 Figs. To appear in the proceedings of the 6th Annual International Conference on Numerical Modeling of Space Plasma Flows in Valencia, Spain, 13-17 June, 2011 (ASTRONUM-2011)