Abstract. We consider the strong field asymptotics for the occurrence of zero modes of certain Weyl-Dirac operators on R 3 . In particular, we are interested in those operators DB for which the associated magnetic field B is given by pulling back a two-form β from the sphere S 2 to R 3 using a combination of the Hopf fibration and inverse stereographic projection. If S 2 β = 0, we show thatas T → +∞. The result relies on Erdős and Solovej's characterisation of the spectrum of DtB in terms of a family of Dirac operators on S 2 , together with information about the strong field localisation of the AharonovCasher zero modes of the latter.