  We start by pedagigically reviewing the problem of large scale magnetic
fields. We explain the acquisition of angular momentum in the general context
of Dark Matter models and we use this result to derive a dynamical mechanism
for magnetic field generation. This mechanism does not produce any magnetic
field for standard CDM, but it does for a large class of other models. We apply
this mechanism in the context of the texture scenario of large-scale structure
formation. Resulting constraints on the texture scenario and other models are
discussed.
