Seed magnetic fields generated by primordial supernova explosions

The origin of the magnetic field in galaxies is an open question in astroph ysics. Several mechanisms have been proposed related, in general, to the ge neration of small seed fields amplified by a dynamo mechanism. In general, these mechanisms have difficulty in satisfying both the requirements of a s ufficiently high strength for the magnetic field and the necessary large co herent scales. We show that the formation of dense and turbulent shells of matter, in the multiple explosion scenario of Miranda & Opher for the forma tion 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 explos ion of Population III objects, a temperature gradient not parallel to a den sity gradient can naturally be established, producing a seed magnetic field through the Biermann battery mechanism. We show that seed magnetic fields similar to 10(-12-)10(-14) G can be produced in this multiple explosion sce nario on scales of the order of clusters of galaxies (with coherence length L similar to 1.8 Mpc) and up to similar to 4.5 x 10(-10) G on scales of ga laxies (L similar to 100 kpc).