Magnetic Confinement

Magnetic confinement uses powerful fields to hold a fusion plasma away from any wall. It is the approach behind tokamaks like Kronos MetroVolt.

Idea

Charged particles follow magnetic field lines

Kronos device

High-field spherical tokamak

Alternative

Inertial confinement (laser compression)

Field

6.0 T on axis, 24.6 T peak

Magnetic confinement is the strategy of holding a fusion plasma — a gas so hot it would destroy any material it touched — inside a cage made of magnetic field rather than matter. Because the plasma is ionized, its charged particles are forced to spiral along field lines, so a suitably shaped magnetic bottle keeps them away from the wall long enough to fuse.

The tokamak is the most developed magnetic-confinement device, and Kronos MetroVolt is a high-field spherical one. The competing approach, inertial confinement, instead compresses a fuel pellet with lasers for a brief instant. Kronos's choice of strong REBCO magnets is what lets a compact magnetic bottle reach reactor conditions.