| National Spherical Torus Experiment | |
|---|---|
 NSTX in 2009 | |
| Device type | Spherical tokamak |
| Location | Princeton, New Jersey, US |
| Affiliation | Princeton Plasma Physics Laboratory |
| Technical specifications | |
| Major radius | 0.85 m (2 ft 9 in) |
| Minor radius | 0.68 m (2 ft 3 in) |
| Magnetic field | 0.3 T (3,000 G) |
| Heating power | 11 MW |
| Plasma current | 1.4 MA |
| History | |
| Year(s) of operation | 1999–present |
| Preceded by | Tokamak Fusion Test Reactor (TFTR) |
| Links | |
| Website | NSTX-U official website |
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The National Spherical Torus Experiment (NSTX) is a magnetic fusion device based on the spherical tokamak concept. It was constructed by the Princeton Plasma Physics Laboratory (PPPL) in collaboration with the Oak Ridge National Laboratory, Columbia University, and the University of Washington at Seattle. It entered service in 1999. In 2012 it was shut down as part of an upgrade program and became NSTX-U, for Upgrade.
Like other magnetic confinement fusion experiments, NSTX studies the physics principles of thermonuclear plasmas—ionized gases with sufficiently high temperatures and densities for nuclear fusion to occur—which are confined in a magnetic field.
The spherical tokamak design implemented by NSTX is an offshoot of the conventional tokamak. Proponents claim that spherical tokamaks have dramatic practical advantages over conventional tokamaks. For this reason the spherical tokamak has seen considerable interest since it was proposed in the late 1980s. However, development remains effectively one generation behind mainline tokamak efforts such as JET. Other major spherical tokamak experiments include the START and MAST at Culham in the UK.