Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Efficient highly-subsonic turbulent dynamo and growth of primordial
  magnetic fields   We present the first study on the amplification of magnetic fields by the
turbulent dynamo in the highly subsonic regime, with Mach numbers ranging from
$10^{-3}$ to $0.4$. We find that for the lower Mach numbers the saturation
efficiency of the dynamo, $(E_{\mathrm{mag}}/E_{\mathrm{kin}})_{\mathrm{sat}}$,
increases as the Mach number decreases. Even in the case when injection of
energy is purely through longitudinal forcing modes,
$(E_{\mathrm{mag}}/E_{\mathrm{kin}})_{\mathrm{sat}}$ $\gtrsim 10^{-2}$ at a
Mach number of $10^{-3}$. We apply our results to magnetic field amplification
in the early Universe and predict that a turbulent dynamo can amplify
primordial magnetic fields to $\gtrsim$ $10^{-16}$ Gauss on scales up to 0.1 pc
and $\gtrsim$ $10^{-13}$ Gauss on scales up to 100 pc. This produces fields
compatible with lower limits of the intergalactic magnetic field inferred from
blazar $\gamma$-ray observations.

34
The categories of this paper are: chem-ph
28
The categories of this paper are: alg-geom
22
The categories of this paper are: chao-dyn
16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
2
The categories of this paper are: math
23
The categories of this paper are: solv-int
12
The categories of this paper are: nucl-th
10
The categories of this paper are: q-bio
17
The categories of this paper are: q-fin
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
13
The categories of this paper are: quant-ph