Vortex Dynamo and Large-Scale Turbulent Structures in a Rotating System

抄録

Turbulent flows subject to the Coriolis force are examined theoretically to study the vortex dynamo or generation of large-scale turbulent structures. A major term in the turbulent vortex-motive force that plays a key role in the mean vorticity equation is shown to be proportional to the angular velocity vector of a rotating system with the proportional coefficient expressed in terms of the helicity. This result shows that the vortical structure with its axis in the zonal direction near the equator is a promising candidate of Saturn’s large atmospheric structures called white spots. Formation of the vortex with its axis normal to the spherical surface, as in typhoons, is also discussed.