Recently it was shown that in salt-fingering convection, symmetry breaking is observed, quantified by the spontaneous generation of helicity [1]. In unstably-stratified turbulence, it was shown that a similar effect can be understood in the two-dimensional, three-component limit [2]. 

In this communication, we show by linear analysis that, analogously to unstably stratified turbulence, in double-diffusive convection in the salt-fingering regime, helicity can be generated in a well-defined region of parameter space, relevant for the dynamics in planetary cores [3].

This finding provides not only a possible theoretical explanation for the spontaneous emergence of helicity, observed in recent numerical simulations [1], but also suggest that helical salt-fingering might be considered as a mechanism to excite and sustain planetary dynamos.

[1] A. E. Fraser, A. van Kan, E. Knobloch, K. Julien, and C. Liu. Spontaneous generation of helicalflows by salt fingers. Journal of Fluid Mechanics, 1020:R1, 2025.

[2] W. Agoua, B. Favier, A. Delache, A. Briard, and W.J.T. Bos. Spontaneous generationand reversal of helicity in anisotropic turbulence. Physical Review E, 103(6):L061101, 2021

[3] S. Varghese, B. Miquel, W.J.T. Bos; Generation of helicity by salt-fingers in the two-dimensional three-component limit. Submitted (2025).