A comparison of observations of Pi B magnetic pulsations at the ground with wide‐angle photometer measurements of the accompanying auroral luminosity fluctuations has found several cases of well‐correlated magnetic and optical pulsations, with periods in the range 15–50 s. This finding strongly suggests that precipitation fluctuations drive at least some of those components of the Pi B signal with periods in this range. We found no luminosity fluctuations associated with the 3‐s enhancement of Pi B pulsations. We modeled the magnetic perturbation under a patch of enhanced E region conductivity as it drifts or as its conductivity changes, for circular and strip patch shapes. These idealized models can reproduce some features of the Pi B signature. Most notably, a monotonic variation in the model parameters can produce a reversal in the sense of polarization rotation. A moderate enhancement in the conductivity of a 1‐km‐wide strip can produce magnetic perturbations with amplitudes typical of Pi B pulsations.