Self-Replicating Three-Dimensional Vortices in Neutrally-Stable
  Stratified Rotating Shear Flows
  A previously unknown instability creates space-filling lattices of 3D
vortices in linearly-stable, rotating, stratified shear flows. The instability
starts from an easily-excited critical layer. The layer intensifies by drawing
energy from the background shear and rolls-up into vortices that excite new
critical layers and vortices. The vortices self-similarly replicate to create
lattices of turbulent vortices. The vortices persist for all time. This
self-replication occurs in stratified Couette flows and in the dead zones of
protoplanetary disks where it can de-stabilize Keplerian flows.
