  Inter-galactic magnetic fields can imprint their structure on the morphology
of blazar-induced gamma ray halos. We show that the halo morphology arises
through the interplay of the source's jet and a two-dimensional surface
dictated by the magnetic field. Through extensive numerical simulations, we
generate mock halos created by stochastic magnetic fields with and without
helicity, and study the dependence of the halo features on the properties of
the magnetic field. We propose a sharper version of the Q-statistics and
demonstrate its sensitivity to the magnetic field strength, the coherence
scale, and the handedness of the helicity. We also identify and explain a new
feature of the Q-statistics that can further enhance its power.
