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The (LHD) is a fusion research device in
Toki, Gifu is a city located in Gifu, Japan. , the city had an estimated population of 58,567 in 24485 households, and a population density of 500 persons per km2. The total area of the city was . Toki is known as one of the largest producers of Japanese ...
, Japan, belonging to the
National Institute for Fusion Science National may refer to: Common uses * Nation or country ** Nationality – a ''national'' is a person who is subject to a nation, regardless of whether the person has full rights as a citizen Places in the United States * National, Maryland, ce ...
. It is the second largest
superconducting Superconductivity is a set of physical properties observed in certain materials where electrical resistance vanishes and magnetic flux fields are expelled from the material. Any material exhibiting these properties is a superconductor. Unlike ...
stellarator A stellarator is a plasma device that relies primarily on external magnets to confine a plasma. Scientists researching magnetic confinement fusion aim to use stellarator devices as a vessel for nuclear fusion reactions. The name refers to th ...
in the world, after the
Wendelstein 7-X The Wendelstein 7-X (abbreviated W7-X) reactor is an experimental stellarator built in Greifswald, Germany, by the Max Planck Institute for Plasma Physics (IPP), and completed in October 2015.heliotron
magnetic field A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and t ...
originally developed in Japan. The objective of the project is to conduct fusion plasma confinement research in a steady state in order to elucidate possible solutions to physics and engineering problems in
helical Helical may refer to: * Helix A helix () is a shape like a corkscrew or spiral staircase. It is a type of smooth space curve with tangent lines at a constant angle to a fixed axis. Helices are important in biology, as the DNA molecule is ...
plasma reactors. The LHD uses
neutral beam injection Neutral-beam injection (NBI) is one method used to heat plasma inside a fusion device consisting in a beam of high-energy neutral particles that can enter the magnetic confinement field. When these neutral particles are ionized by collision with ...
, ion cyclotron radio frequency (ICRF), and
electron cyclotron resonance heating A tokamak (; russian: токамáк; otk, 𐱃𐰸𐰢𐰴, Toḳamaḳ) is a device which uses a powerful magnetic field to confine plasma in the shape of a torus. The tokamak is one of several types of magnetic confinement devices being ...
(ECRH) to heat the plasma, much like conventional
tokamak A tokamak (; russian: токамáк; otk, 𐱃𐰸𐰢𐰴, Toḳamaḳ) is a device which uses a powerful magnetic field to confine plasma in the shape of a torus. The tokamak is one of several types of magnetic confinement devices being ...
s.


History

* Design finalized 1987 * Start of construction 1990 * Plasma operations from 1998 **Neutral beam injection of 3 MW was used in 1999. **In 2005 it maintained a plasma for 3,900 seconds. * In 2006 a new helium cooler was added. Using the new cooler, by 2018 a total of 10 long term operations have been achieved, reaching a maximum power level of 11.833 kA. * To aid public acceptance, an exhaust system was designed to catch and filter the radioactive
tritium Tritium ( or , ) or hydrogen-3 (symbol T or H) is a rare and radioactive isotope of hydrogen with half-life about 12 years. The nucleus of tritium (t, sometimes called a ''triton'') contains one proton and two neutrons, whereas the nucleus ...
the fusion process produces.


See also

*
Fusion reactor Fusion power is a proposed form of power generation that would generate electricity by using heat from nuclear fusion reactions. In a fusion process, two lighter atomic nuclei combine to form a heavier nucleus, while releasing energy. Devices de ...
* National Institutes of Natural Sciences, Japan


References


External links


''Large Helical Device'' Website
good diagrams (worth archiving page)
Super Dense Core plasmas in LHD. Harris. 2008
16 slides. advanced - inc ballooning mode and future development options {{coord, 35, 19, 34, N, 137, 10, 07, E, source:kolossus-jawiki, display=title Fusion power Stellarators Toki, Gifu