  As soon as the geometry expands quasi-exponentially the plasma sources are
customarily tuned to zero as if the duration of the inflationary phase was
immaterial for the gauge field fluctuations at large-scale. The serendipitous
disappearance of the plasma (or even the partial neglect of its effects)
depends on the symmetries of the system which are, in four space-time
dimensions and in the simplest Abelian case, the invariance under Weyl
rescaling and the electromagnetic duality symmetry. The quantum, thermal and
conducting initial conditions of inflationary magnetogenesis are classified and
discussed with the aim of determining when plasma effects can be effectively
disregarded. The speculative implications of a non-degenerate monopole plasma
for the conservation of the large-scale electric flux are briefly examined.
