Bumpy torus

The bumpy torus is a class of magnetic fusion energy devices that consist of a series of magnetic mirrors connected end-to-end to form a closed torus. Such an arrangement is not stable on its own, and most bumpy torus designs use secondary fields or relativistic electrons to create a stable field inside the reactor. The main disadvantage of magnetic mirror confinement, that of excessive plasma leakage, is circumvented by the arrangement of multiple mirrors end-to-end in a ring.

Bumpy torus designs were an area of active research in the 1960s and 70s, notably with the ELMO (ELectro Magnetic Orbit) Bumpy Torus at the Oak Ridge National Laboratory, but these demonstrated problems and most research on the concept has ended.