User:SimonHarvey/Sandbox/Helically Symmetric Experiment

The Helically Symmetric eXperiment (HSX) is an experimental plasma confinement device whose design principles are hoped to be incorporated into a fusion reactor. The HSX is a modular coil stellarator which is a toroidal shaped pressure vessel with external electromagnets which generate a magnetic field for the purpose of containing a plasma.

Goals
Stellarators use magnets to keep the hot plasma from coming in contact with the vessel walls. This differs from a tokamak design where a large current is put through the plasma keeping the plasma contained through the Lorenz force. Stellarators do not require large currents to flow throughout the plasma, however more energy is lost when the ions that make up the plasma hit the vessel wall. This is known as transport and is a large problem of stellarators. HMX is a stellarator that features a helically symmetric magnetic field which reduces this transport.

The role of quasi-symmetry
In a traditional stellarator, as the ions travel around the pressure vessel under magnetic confinement they experiences a force...

The HSX is currently the only operating quasi-symmetric stellarator and is operated by the University of Wisconsin-Madison.

Results
The HMX has detected a measurable decrease in transport