What triggers geomagnetic polarity reversals and sets their rate?

The axial dipole reverses irregularly, at a mean rate of roughly 4 to 5 per Myr over the last few Myr and essentially zero during superchrons such as the Cretaceous Normal Superchron (about 121 to 83 Ma). Identify the magnetohydrodynamic mechanism in the rotating, convecting outer core (Ekman number $E \sim 10^{-15}$, magnetic Prandtl number $\mathrm{Pm} \sim 10^{-6}$) that initiates reversals and controls their rate. An answer is a mechanism demonstrated in dynamo simulations at Earth-like parameter ratios that reproduces the observed reversal statistics (rate, duration of transitions, excursion frequency).

Dynamo simulations in the rapidly rotating asymptotic regime that reproduce paleomagnetic reversal-rate and transition statistics with an identified triggering flow.