Central Solenoid

The core magnet that induces and ramps the plasma current.

The central solenoid acts like a transformer primary, its changing current inducing the plasma current. In a compact spherical tokamak, space for it is tight — part of the centre-column challenge.

The central solenoid induces and ramps the plasma current like a transformer primary, and in a compact spherical tokamak there is barely room for it — part of the centre-column squeeze. Its limited flux swing (volt-seconds) is one reason HYPERION leans on non-inductive current drive and a 15.2% bootstrap fraction to sustain steady state.