Jacques M. Wagstaff, Robi Banerjee, Dominik Schleicher, Guenter Sigl
In this letter we show that the Universe is already strongly magnetised at very early epochs during cosmic evolution. Our calculations are based on the efficient amplification of weak magnetic seed fields, which are unavoidably present in the early Universe, by the turbulent small-scale dynamo (SSD). We identify at least one epoch during the radiation dominated regime where all the necessities for the SSD to work are fulfilled. Hence, at scales of $l_c\sim0.3$ pc, the comoving field strength due to this mechanism will be $B_0\sim0.35\varepsilon^{1/2}$ nG at the present time, where $\varepsilon$ is the saturation efficiency.
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http://arxiv.org/abs/1304.4723
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