Here's how I understand it: - The simplest closed magnetic configuration is a torus. You can't smoothly "comb a hairy ball", but you can comb a hairy torus. -

Here's how I understand it: - The simplest closed magnetic configuration is a torus. You can't smoothly "comb a hairy ball", but you can comb a hairy torus. - For a toroidal plasma to be stable, it needs magnetic field components both the "long way" around (toroidal), and the "short way" around (poloidal). - The tokamak generates the poloidal field from a current within the plasma, whereas the stellerator imposes that component with external magnets. So you could make a "natural" argument either way, and I was asking the grandparent in what sense the stellerator is more "natural".