  The origin of the first magnetic fields in the Universe is a standing problem
in cosmology. Intergalactic magnetic fields (IGMFs) may be an untapped window
to the primeval Universe, providing further constrains on magnetogenesis. We
demonstrate the feasibility of using ultra-high-energy cosmic rays (UHECRs) to
constrain the helicity of IGMFs by performing simulations of cosmic-ray
propagation in simple magnetic field configurations. We show that the first
harmonic moments of the arrival distribution of UHECRs may be used to measure
the absolute value of the helicity and its sign.
