We re-analyze the production of seed magnetic fields during Inflation in (R/m^2)^n F_{mu u}F^{mu u} and I F_{mu u}F^{mu u} models, where n is a positive integer, R the Ricci scalar, m a mass parameter, and I propto eta^alpha a power-law function of the conformal time eta, with alpha a positive real number. If m is the electron mass, the produced fields are uninterestingly small for all n. Taking m as a free parameter we find that, for n geq 2, the produced magnetic fields can be sufficiently strong in order to seed dynamo mechanism and then to explain galactic magnetism. For alpha gtrsim 2, there is always a window in the parameters defining Inflation such that the generated magnetic fields are astrophysically interesting. Moreover, if Inflation is (almost) de Sitter and the produced fields almost scale-invariant (alpha simeq 4), their intensity can be strong enough to directly explain the presence of microgauss galactic magnetic fields.
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