Toroidal

Toroidal is an adjective that describes something shaped like or related to a torus, a doughnut-shaped object. In three-dimensional space, a torus is generated by revolving a circle in its plane around an axis coplanar with the circle, producing a ring-shaped solid or surface with a central hole.

In topology and geometry, the torus is the product of two circles, often represented as S^1 × S^1. A two-dimensional torus has genus 1 and is a fundamental example in the study of surfaces. The term toroidal is also used for coordinate systems, such as toroidal coordinates, which are particularly suited to problems with the geometry of a torus.

In electrical engineering, toroidal components use a ring-shaped magnetic core to confine magnetic flux, yielding compact inductors and transformers with reduced electromagnetic interference. In physics, toroidal magnetic confinement devices—most notably tokamaks and stellarators—aim to confine hot plasma in a toroidal chamber using magnetic fields.

The term toroidal derives from the Latin torus, meaning a cushion or doughnut. The word is widely used across disciplines to denote torus-like shapes or properties.