World Record ß

Spherical tokamaks are theoretically predicted to have higher plasma containment efficiency than conventional tokamaks. A measure of this is ß, the ratio of plasma pressure to magnetic field pressure. To test this in START, a Neutral Beam Injector (NBI) was loaned to Culham by the Oak Ridge National Laboratory, USA, and used to provide additional heating of the START plasma. A new world record in ß, was achieved, reaching 40% on START, trebling the previous record of 12.6% on the DIII-D tokamak at General Atomics, San Diego (see figure).

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