CERN-TH/2003-307
astro-ph/0312614

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THE MAGNETIZED UNIVERSE

Massimo Giovannini 1


CERN, Theoretical Physics Division, CH-1211 Geneva 23, Switzerland


Abstract. Cosmology, high-energy physics and astrophysics are converging on the study of large-scale magnetic fields. While the experimental evidence for the existence of large-scale magnetization in galaxies, clusters and superclusters is rather compelling, the origin of the phenomenon remains puzzling especially in light of the most recent observations. The purpose of the present review is to describe the physical motivations and some of the open theoretical problems related to the existence of large-scale magnetic fields.


Table of Contents

A TRIPLE POINT

FROM ALFVÉN TO ROSAT

LARGE-SCALE MAGNETIC FIELDS OBSERVATIONS
Zeeman splitting
Synchrotron emission
Faraday Rotation Measurements
Magnetic fields in the Milky Way
Magnetic fields in external galaxies
Magnetic fields in Abell clusters
Magnetic fields in superclusters

GLOBALLY NEUTRAL PLASMAS
Qualitative aspects of plasma dynamics
Kinetic and fluid descriptions
From one-fluid equations to MHD
The Alfvén theorems
Magnetic diffusivity equation
The dynamo mechanism

MAGNETIC FIELDS IN CURVED BACKGROUNDS
The standard cosmological model
Gauge fields in FRW Universes
Physical scales in the evolution of magnetic fields
Charge and current density fluctuations
Inverse cascades
Hypermagnetic fields

TWO APPROACHES TO THE ORIGIN
Inhomogeneous MHD equations
Inflationary mechanisms
Inside the Hubble radius
Mixed mechanisms

EFFECTS OF PRIMORDIAL MAGNETIC FIELDS
Electroweak epoch
Big-bang nucleosynthesis epoch

CMB PHYSICS AN MAGNETIC FIELDS
Large-scale magnetic fields and CMB anisotropies
Faraday rotation of CMB
Relic gravitational waves

GRAVITATING MAGNETIC FIELDS

CONCLUDING REMARKS

COMPLEMENTS ON MHD DESCRIPTION

REFERENCES



1e-mail address: massimo.giovannini@cern.ch Back.

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