Chandrasekhar–Kendall function
Chandrasekhar–Kendall functions are the eigenfunctions of the curl operator derived by Subrahmanyan Chandrasekhar and P. C. Kendall in 1957 while attempting to solve the force-free magnetic fields. The functions were independently derived by both, and the two decided to publish their findings in the same paper.
Source: Wikipedia — Chandrasekhar–Kendall function (CC BY-SA 4.0)