Growth of helicity in salt-finger convection in the two-dimensional three-component limit

We present an analytical investigation of the global helicity budget associated with the salt-fingering instability within the two-dimensional, three-component framework. Our analysis shows that in the region of parameter space corresponding to salt-fingering, helicity amplification occurs when the Rayleigh ratio–quantifying the relative strength of salinity to temperature gradients–exceeds a critical threshold. This finding provides a possible theoretical explanation for the spontaneous emergence of helicity, observed in recent numerical simulations.