Many concepts have been proposed for sustained fusion reactors, but the main challenge inhibiting major progress is plasma confinement. The “Centrifugal Mirror Confinement” scheme incorporates supersonic rotation into a magnetic mirror device, stabilizing and heating the plasma into a more controllable state. This solution is promising for its engineering simplicity and steady-state operation, and it is under investigation in the Centrifugal Mirror Fusion Experiment (CMFX) at the University of Maryland.

Plasma rotation is driven by an axial magnetic field and a radial electric field that lead to E×B velocity drifts in the azimuthal direction. This rotation resolves many of the shortcomings of a conventional magnetic mirror by suppressing instabilities, increasing confinement time, increasing density, and heating the plasma. CMFX was designed and constructed in roughly a year and a half, and it has been in operation since October 2022. A video overview can be found here.

Internally, there are several key components including the limiters, central conductor, and insulators. High voltage is applied to the central conductor and each “layer” of plasma is at a different voltage. An electrically insulating material is required to prevent the applied voltage from shorting on the grounded chamber. CMFX has a unique requirement among fusion devices: While other fusion experiments have utilized electrically insulating materials, CMFX and similar centrifugal mirror devices necessitate electrical insulators as an integral part of their design.