NSTX
From Wikipedia, the free encyclopedia
- Not to be confused with the IP-over-DNS tunneling software by the same name.
The NSTX, or National Spherical Torus eXperiment, is a magnetic fusion device that 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.
First plasma was obtained inside the NSTX on Friday, February 12, 1999 at 6:06 p.m. NSTX is being used to study the physics principles of spherically shaped plasmas -- hot ionized gases in which nuclear fusion will occur under the appropriate conditions of temperature, density, and confinement in a magnetic field. Fusion is the energy source of our Sun and all the stars.
Magnetic fusion experiments use plasmas comprised of one or more of the isotopes of hydrogen. For example, in 1994, PPPL's Tokamak Fusion Test Reactor (TFTR) produced a world-record 10.7 megawatts of fusion power from a plasma comprised of equal parts of deuterium and tritium, the fuel mix most likely to be used in future commercial fusion power reactors (and ITER). NSTX is a "proof of principle" experiment and therefore employs deuterium plasmas only. If successful it will be followed by similar devices, eventually including a demonstration power reactor, burning deuterium-tritium fuel.
NSTX produces a plasma that is shaped like a sphere with a hole through its center (a "cored apple" profile), different from the "donut" shaped plasmas of conventional tokamaks. This innovative plasma configuration may have several advantages, a major one being the ability to confine a higher plasma pressure for a given magnetic field strength. Since the amount of fusion power produced is proportional to the square of the plasma pressure, the use of spherically shaped plasmas could allow the development of smaller, more economical fusion reactors. NSTX's potential may be further enhanced by its ability to produce a high "bootstrap" electric current. This self-driven internal plasma current would significantly reduce the amount of external power needed to heat and confine the plasma. The NSTX is similar to the MAST experiment in the UK.
Technical specifications:
- Major radius: 0.85m
- Minor radius: 0.68m
- Plasma current: 1 mega-amp
- Toroidal field: 0.6 tesla
- Heating and current drive: 6-11 megawatts
- Flat-top time: 1.6-5 seconds
