Cosmological 'seed' magnetic field from inflation

The scalar-field-inflation-modified hot big bang model (Ratra and Peebles, 1988; Ratra, 1989) is extended by adding an inflation epoch coupling term between the scalar field Phi responsible for inflation and an Abelian gauge field A(mu). It is shown that the inflation based mechanism can generate a present intergalactic magnetic field that might be as large as about 10 exp -10 G. This is an example of a primeval seed magnetic field, which might be amplified by anisotropic protogalactic collapse and galactic differential rotation to produce the present galactic magnetic fields. The paper describes the model and the derivation of the magnetic-field two-point correlation function.