Interstellar and intergalactic dynamos

Michal Hanasz, Michal.Hanasz@astri.uni.torun.pl, Centre for Astronomy, Nicolaus Copernicus University, Poland

Abstract
I am going to review recent developments of amplification models of galactic and intergalactic magnetic field. The most popular scenarios engage variety of physical mechanisms, involving turbulence generation on a wide range of physical scales, involving supernova-driven turbulence, buoyancy of hot gas and cosmic rays as well as magnetorotational instability. Another model relies on galaxy interaction, which efficiently generate galactic and intergalactic magnetic fields during multiple mergers. The overall picture of cosmic magnetisation seems to involve both internal galactic processes and at the same time galactic interactions. A unified scenario has not yet emerged, however observations of galactic magnetic fields provide a growing collection of interesting cases which are challenging for theoretical models.