The National Compact Stellarator Experiment (NCSX) is a plasma confinement experiment that was being conducted at the Princeton Plasma Physics Laboratory. NCSX used magnets and layout designed through massively parallel computing to find the optimal shape for the reactor vessel, leading to a compact device. The project was cancelled on 22 May 2008 due to a failure to meet budgetary constraints.
NCSX is a variation of the stellarator concept, with a much lower aspect ratio than a typical stellarator. One of the advantages of correctly designed stellarators is that the confined plasma is passively stable when a steady magnetic field is applied, whereas tokamaks require an array of active control strategies to stabilize the plasma, even under a constant magnetic field. Up to 12 MW of auxiliary heating power would have been available to the NCSX chamber, consisting of 6 MW from tangential neutral beam injection, and 6MW from radio-frequency (RF) heating. Up to 3 MW of electroncyclotron heating would also have been available in future iterations of the design. The assembly tolerances were very tight and required state of the art use of metrology systems including Laser Tracker and photogrammetry equipment. $50 million of additional funding was needed, spread over the next 3 years, to complete the assembly within tolerance requirements. Components for the Stellarator were measured with 3d laser scanning, and inspected to design models at multiple stages in the manufacturing process.