  The origin of the magnetic field in galaxies is an open question in
astrophysics. Several mechanisms have been proposed related, in general, with
the generation of small seed fields amplified by a dynamo mechanism. In
general, these mechanisms have difficulty in satisfying both the requirements
of a sufficiently high strength for the magnetic field and the necessary large
coherent scales. We show that the formation of dense and turbulent shells of
matter, in the multiple explosion scenario of Miranda and Opher (1996, 1997)
for the formation of the large-scale structures of the Universe, can naturally
act as a seed for the generation of a magnetic field. During the collapse and
explosion of Population III objects, a temperature gradient not parallel to a
density gradient can naturally be established, producing a seed magnetic field
through the Biermann battery mechanism. We show that seed magnetic fields $\sim
10^{-12}-10^{-14}G$ can be produced in this multiple explosion scenario on
scales of the order of clusters of galaxies (with coherence length $L\sim
1.8Mpc$) and up to $\sim 4.5\times 10^{-10}G$ on scales of galaxies ($L\sim 100
kpc$).

Astrophysics