Spontaneous generation and reversal of helicity in anisotropic turbulence

Helicity plays an important role in spectacular geophysical phenomena such as hurricanes or the generation of terrestrial magnetic field. The present investigation shows how helicity can be created a statistically homogeneous but anisotropic flow, driven by buoyancy. If flow is close enough to two-dimensional limit, spontaneous symmetry breaking leads mean helicity. In particular, we explain these observations identifying simple linear mechanism, relevance which illustrated simulations unstably stratified turbulence conducting fluid on field imposed. Finally it shown that self-organized state displays dynamical reversals sign