ASDEX Upgrade (''Axially Symmetric Divertor Experiment'') is a

divertor In magnetic confinement fusion, a divertor is a magnetic field configuration which diverts the heat and particles escaped from the magnetically confined plasma to dedicated plasma-facing components, thus spatially separating the region plasma ...

tokamak A tokamak (; ) is a device which uses a powerful magnetic field generated by external magnets to confine plasma (physics), plasma in the shape of an axially symmetrical torus. The tokamak is one of several types of magnetic confinement fusi ...

at the

Max-Planck-Institut für Plasmaphysik The Max Planck Institute for Plasma Physics (, IPP) is a physics institute investigating the physical foundations of a fusion power plant. The IPP is an institute of the Max Planck Society, part of the European Atomic Energy Community, and an as ...

Garching Garching bei München (, ''Garching near Munich'') or Garching is a city in Bavaria, near Munich. It is the home of several research institutes and university departments, located at Campus Garching. History Spatial urban planning Garching was ...

that went into operation in 1991. At present, it is

Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

's second largest fusion experiment after stellarator

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.plasma properties, particularly the plasma density and pressure and the wall load, have been adapted in ASDEX Upgrade to the conditions that will be present in a future fusion power plant. ASDEX Upgrade is, compared to other international tokamaks, a midsize tokamak experiment. It began operation in 1991 and it succeeds the ASDEX experiment, which was in operation from 1980 until 1990. One innovative feature of the ASDEX Upgrade experiment is its all-

tungsten Tungsten (also called wolfram) is a chemical element; it has symbol W and atomic number 74. It is a metal found naturally on Earth almost exclusively in compounds with other elements. It was identified as a distinct element in 1781 and first ...

first wall; tungsten is a good choice for the

first wall In nuclear fusion power research, the plasma-facing material (or materials) (PFM) is any material used to construct the plasma-facing components (PFC), those components exposed to the plasma within which nuclear fusion occurs, and particularly t ...

of a tokamak because of its very high

melting point The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state of matter, state from solid to liquid. At the melting point the solid and liquid phase (matter), phase exist in Thermodynamic equilib ...

(over 3000 degrees Celsius) which enables it to stand up to the very high heat fluxes emanating from the hot plasma at the heart of the tokamak; however there are also problems associated with a tungsten first wall, such as tungsten's tendency to ionise at high temperatures, "polluting" the plasma and diluting the

deuterium Deuterium (hydrogen-2, symbol H or D, also known as heavy hydrogen) is one of two stable isotopes of hydrogen; the other is protium, or hydrogen-1, H. The deuterium nucleus (deuteron) contains one proton and one neutron, whereas the far more c ...

tritium Tritium () or hydrogen-3 (symbol T or H) is a rare and radioactive isotope of hydrogen with a half-life of ~12.33 years. The tritium nucleus (t, sometimes called a ''triton'') contains one proton and two neutrons, whereas the nucleus of the ...

fuel mix. Furthermore, as a high ''Z'' material, radiation from fully ionized tungsten in the plasma is several orders of magnitude higher than that of other proposed first wall components such as carbon fibre composites (CFCs) or

beryllium Beryllium is a chemical element; it has Symbol (chemistry), symbol Be and atomic number 4. It is a steel-gray, hard, strong, lightweight and brittle alkaline earth metal. It is a divalent element that occurs naturally only in combination with ...

. This result allows for far less tungsten to "contaminate" a proposed break-even plasma. ASDEX Upgrade will examine ways to overcome this problem, in preparation for the construction of

ITER ITER (initially the International Thermonuclear Experimental Reactor, ''iter'' meaning "the way" or "the path" in Latin) is an international nuclear fusion research and engineering megaproject aimed at creating energy through a fusion process s ...

's first wall. The experiment has an overall radius of 5 metres, a gross weight of 800

metric ton The tonne ( or ; symbol: t) is a unit of mass equal to 1,000 kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton in the United States to distinguish it from the non-metric units of the sh ...

s, a maximum magnetic field strength of 3.1

tesla Tesla most commonly refers to: * Nikola Tesla (1856–1943), a Serbian-American electrical engineer and inventor * Tesla, Inc., an American electric vehicle and clean energy company, formerly Tesla Motors, Inc. * Tesla (unit) (symbol: T), the SI-d ...

, a maximum plasma current of 1.6 megaampere and maximum heating power of up to 27

megawatt The watt (symbol: W) is the unit of Power (physics), power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantification (science), quantify the rate of Work ...

. Plasma heating and current drive in the ASDEX Upgrade is derived from several sources, namely 1 MW of

ohmic heating Joule heating (also known as resistive heating, resistance heating, or Ohmic heating) is the process by which the passage of an electric current through a conductor produces heat. Joule's first law (also just Joule's law), also known in countr ...

, 20 MW of

neutral beam injection Neutral-beam injection (NBI) is one method used to heat Plasma (physics), plasma inside a Tokamak, fusion device consisting in a beam of high-energy neutral particles that can enter the magnetic confinement field. When these neutral particles are i ...

, 6 MW via

ion cyclotron resonance Ion cyclotron resonance is a phenomenon related to the movement of ions in a magnetic field. It is used for accelerating ions in a cyclotron, and for measuring the masses of an ionized analyte in mass spectrometry, particularly with Fourier transfor ...

heating (ICRH) at frequencies between 30 and 120

megahertz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose formal expression in terms of SI base ...

, and 2 x 2 MW of

electron cyclotron resonance Electron cyclotron resonance (ECR) is a phenomenon observed in plasma physics, condensed matter physics, and accelerator physics. It happens when the frequency of incident radiation coincides with the natural frequency of rotation of electrons in ...

heating (ECRH) at 140

gigahertz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose formal expression in terms of SI base un ...

. It has 16 toroidal field coils and 12 poloidal field coils. Three large flywheel generators feed the 580 MVA pulsed power supply system for the magnetic confinement and plasma heating.

ASDEX

ASDEX (with a major radius R=1.65m, minor radius a=0.4m, and plasma current Ip≤500kA) started operation in 1980. In 1991, it was dismantled by personnel of the Southwestern Institute of Physics (SWIP), transported to Chengdu, China, and its main components were used to build the

HL-2A HL-2A (Huan-Liuqi-2A) is a medium-sized tokamak for fusion research in Chengdu, China. It was constructed by the China National Nuclear Corporation from early 1999 to 2002, based on the main components (magnet coils and plasma vessel) of the form ...

. The

H-mode In plasma physics and magnetic confinement fusion, the high-confinement mode (H-mode) is a phenomenon observed in toroidal fusion plasmas such as tokamaks. In general, plasma energy confinement degrades as the applied heating power is increased. Ab ...

was discovered in ASDEX in 1982.

External links

ASDEX Upgrade homepage

ASDEX Upgrade technical specs

References

{{Authority control Tokamaks

ASDEX

See also

External links

References