Large Helical Device
Encyclopedia
The
is a fusion research device in Toki, Gifu
, Japan and is the largest superconducting stellarator
in the world, employing a heliotron magnetic field
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 plasma reactors
. The LHD uses neutral beam injection
, ion
cyclotron
radio frequency
(ICRF), and electron
cyclotron
resonance
heating (ECRH) to heat the plasma, much like conventional tokamak
s.
is a fusion research device in Toki, Gifu
Toki, Gifu
is a city in Gifu Prefecture, Japan. The city is located on the Honshū island, to the southeast of Gifu City, the prefectural capital. The Toki River runs through the downtown area. Toki is known as one of the largest producers of Japanese pottery. The products made in the region are generally...
, Japan and is the largest superconducting stellarator
Stellarator
A stellarator is a device used to confine a hot plasma with magnetic fields in order to sustain a controlled nuclear fusion reaction. It is one of the earliest controlled fusion devices, first invented by Lyman Spitzer in 1950 and built the next year at what later became the Princeton Plasma...
in the world, employing a heliotron magnetic field
Magnetic field
A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...
originally developed in Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
. The objective of the project is to conduct fusion
Nuclear fusion
Nuclear fusion is the process by which two or more atomic nuclei join together, or "fuse", to form a single heavier nucleus. This is usually accompanied by the release or absorption of large quantities of energy...
plasma
Plasma (physics)
In physics and chemistry, plasma is a state of matter similar to gas in which a certain portion of the particles are ionized. Heating a gas may ionize its molecules or atoms , thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions...
confinement research in a steady state in order to elucidate possible solutions to physics and engineering problems in helical plasma reactors
Fusion power
Fusion power is the power generated by nuclear fusion processes. In fusion reactions two light atomic nuclei fuse together to form a heavier nucleus . In doing so they release a comparatively large amount of energy arising from the binding energy due to the strong nuclear force which is manifested...
. The LHD uses neutral beam injection
Neutral Beam Injection
To initiate a sustained fusion reaction, it is usually necessary to use many methods to heat the plasma, including RF heating, electron cyclotron resonance heating , ion cyclotron resonance heating , and neutral beam injection....
, ion
Ion
An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...
cyclotron
Cyclotron
In technology, a cyclotron is a type of particle accelerator. In physics, the cyclotron frequency or gyrofrequency is the frequency of a charged particle moving perpendicularly to the direction of a uniform magnetic field, i.e. a magnetic field of constant magnitude and direction...
radio frequency
Radio frequency
Radio frequency is a rate of oscillation in the range of about 3 kHz to 300 GHz, which corresponds to the frequency of radio waves, and the alternating currents which carry radio signals...
(ICRF), and electron
Electron
The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...
cyclotron
Cyclotron
In technology, a cyclotron is a type of particle accelerator. In physics, the cyclotron frequency or gyrofrequency is the frequency of a charged particle moving perpendicularly to the direction of a uniform magnetic field, i.e. a magnetic field of constant magnitude and direction...
resonance
Resonance
In physics, resonance is the tendency of a system to oscillate at a greater amplitude at some frequencies than at others. These are known as the system's resonant frequencies...
heating (ECRH) to heat the plasma, much like conventional tokamak
Tokamak
A tokamak is a device using a magnetic field to confine a plasma in the shape of a torus . Achieving a stable plasma equilibrium requires magnetic field lines that move around the torus in a helical shape...
s.