Primordial magnetic field amplification from turbulent reheating

• Autores: Calzetta, Esteban Adolfo; Kandus, Alejandra
• Año de publicación: 2010
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Cosmic Magnetic Fields Theory; Magnetohydrodynamics
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

We analyze the possibility of primordial magnetic field amplification by a stochastic large scale kinematic dynamo during reheating. We consider a charged scalar field minimally coupled to gravity. During inflation this field is assumed to be in its vacuum state. At the transition to reheating the state of the field changes to a many particle/anti-particle state. We characterize that state as a fluid flow of zero mean velocity but with a stochastic velocity field. We compute the scale-dependent Reynolds number Re(k), and the characteristic times for decay of turbulence, td and pair annihilation ta, finding ta ≪ td. We calculate the rms value of the kinetic helicity of the flow over a scale Γ and show that it does not vanish. We use this result to estimate the amplification factor of a seed field from the stochastic kinematic dynamo equations. Although this effect is weak, it shows that the evolution of the cosmic magnetic field from reheating to galaxy formation may well be more complex than as dictated by simple flux freezing. © 2010 IOP Publishing Ltd and SISSA.
Fil: Calzetta, Esteban Adolfo. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina
Fil: Kandus, Alejandra. Universidade Estadual de Santa Cruz; Brasil