  This work introduces the "potential vorticity bucket brigade," a mechanism
for explaining the resilience of vortex structures in magnetically confined
fusion plasmas and geophysical flows. Drawing parallels with zonal jet
formation, we show how inhomogeneous patterns of mixing can reinforce, rather
than destroy non-zonal flow structure. We accomplish this through an exact
stochastic Lagrangian representation of vorticity transport, together with a
near-integrability property, which relates coherent flow topology to fluid
relabeling symmetries. We demonstrate these ideas in the context of
gradient-driven magnetized plasma turbulence, though the tools we develop here
are model-agnostic and applicable beyond the system studied here.
