  We studied the impact of field heterogeneity on entrainment in a system of
uniformly interacting phase oscillators. Field heterogeneity is shown to induce
dynamical heterogeneity in the system. In effect, the heterogeneous field
partitions the system into interacting groups of oscillators that feel the same
local field strength and phase. Based on numerical and analytical analysis of
the explicit dynamical equations derived from the periodically forced Kuramoto
model, we found that the heterogeneous field can disrupt entrainment at
different field frequencies when compared to the homogeneous field. This
transition occurs when the phase- and frequency-locked synchronization between
groups of oscillators is broken at a critical field frequency, causing each
group to enter a new dynamical state (disrupted state). Strikingly, it is shown
that disrupted dynamics can differ between groups.
