  Magnetic fields in the early universe could have played an important role in
sourcing cosmological perturbations. While not the dominant source, even a
small contribution might be traceable through its intrinsic non-Gaussianity.
Here we calculate analytically the one, two and three point statistics of the
magnetic stress energy resulting from tangled Gaussian fields, and confirm
these with numerical realizations of the fields. We find significant
non-Gaussianity, and importantly predict higher order moments that will appear
between the scalar, vector and tensor parts of the stress energy (e.g.
scalar-tensor-tensor moments). Such higher order cross correlations are a
generic feature of non-linear theories and could prove to be an important probe
of the early universe.
