![COMPASS tokamak](https://upload.wikimedia.org/wikipedia/commons/a/a0/COMPASS_tokamak.jpg)
COMPASS, short for Compact Assembly, is a compact
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 ...
fusion energy
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 ...
device originally completed at the
Culham Science Centre
The Culham Centre for Fusion Energy (CCFE) is the UK's national laboratory for fusion research. It is located at the Culham Science Centre, near Culham, Oxfordshire, and is the site of the Joint European Torus (JET), Mega Ampere Spherical Toka ...
in 1989, upgraded in 1992, and operated until 2002. It was designed as a flexible research facility dedicated mostly to plasma physics studies in circular and D-shaped
plasmas.
When it was decommissioned at Culham, it was offered to the European Commission and found a new home at the Institute of Plasma Physics of the
Czech Academy of Sciences
The Czech Academy of Sciences (abbr. CAS, cs, Akademie věd České republiky, abbr. AV ČR) was established in 1992 by the Czech National Council as the Czech successor of the former Czechoslovak Academy of Sciences and its tradition goes back ...
in
Prague
Prague ( ; cs, Praha ; german: Prag, ; la, Praga) is the capital and List of cities in the Czech Republic, largest city in the Czech Republic, and the historical capital of Bohemia. On the Vltava river, Prague is home to about 1.3 milli ...
where it began operations once again in 2006.
It officially ended its experimental runs on 20 August 2021 and will be disassembled to leave room for a new device, COMPASS-U.
History
The first plasma in COMPASS was produced in 1989 in a C-shaped
vacuum
A vacuum is a space devoid of matter. The word is derived from the Latin adjective ''vacuus'' for "vacant" or " void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Physicists often di ...
vessel, i.e., in a simpler vessel with a circular cross-section. Pioneering experiments followed, including for example the
ITER-relevant tests of
magnetic field correction with saddle coils for
Resonant magnetic perturbations Resonant magnetic perturbations (RMPs) are a special type of magnetic field perturbations used to control burning plasma instabilities called edge-localized modes (ELMs) in magnetic fusion devices such as tokamaks. The efficiency of RMPs for contr ...
(RMP) experiments or experiments with non-inductive current drive in plasma.
The operation of tokamak was restarted with a D-shaped vacuum vessel in 1992. The operation mode with high plasma confinement (
H-mode) was achieved, which represents a reference operation ("standard scenario") for the ITER tokamak. The COMPASS tokamak is one of the smallest tokamaks able to operate in H-mode, with a major radius 0.6 m and height of approximately 0.7 m. Due to its size and shape, the COMPASS plasmas correspond to one tenth (in the linear scale) of the ITER plasmas. Besides COMPASS, there are only two operational tokamaks in Europe with ITER-like configuration capable of H-mode, the
Joint European Torus
The Joint European Torus, or JET, is an operational Magnetic confinement fusion, magnetically confined Plasma (physics), plasma physics experiment, located at Culham Centre for Fusion Energy in Oxfordshire, United Kingdom, UK. Based on a tokamak ...
(JET) at Culham and the
ASDEX Upgrade
ASDEX Upgrade (''Axially Symmetric Divertor Experiment'') is a divertor tokamak, that went into operation at the Max-Planck-Institut für Plasmaphysik, Garching in 1991. At present, it is Germany's second largest fusion experiment after stella ...
at the
Institut für Plasmaphysik in
Garching, Germany.
In 2002, British scientists started alternative research on larger, spherical tokamak
MAST. Operation of COMPASS was discontinued due to insufficient resources for the operation of both tokamaks, however, the planned research program was not complete. The European Commission and UKAEA sent COMPASS to the Institute of Plasma Physics in
Prague
Prague ( ; cs, Praha ; german: Prag, ; la, Praga) is the capital and List of cities in the Czech Republic, largest city in the Czech Republic, and the historical capital of Bohemia. On the Vltava river, Prague is home to about 1.3 milli ...
in the autumn of 2004. The machine restarted operations in 2006 and operated continually until its last "shot" on 20 August 2021. During its operational time in Prague, COMPASS carried out 21,000 experimental shots.
, plans are to dispose of COMPASS to make way for a significantly larger machine, COMPASS-U (for Upgrade).
COMPASS and COMPASS-U
See also
*
List of fusion experiments
Experiments directed toward developing fusion power are invariably done with dedicated machines which can be classified according to the principles they use to confine the plasma fuel and keep it hot.
The major division is between magnetic co ...
*
ELM (Edge Localized Mode)
*
Ball-pen probe
A ball-pen probe is a modified Langmuir probe used to measure the plasma potential in magnetized plasmas. The ball-pen probe balances the electron and ion saturation currents, so that its floating potential is equal to the plasma potential. Be ...
*
Langmuir probe
*
Thomson scattering
Thomson scattering is the elastic scattering of electromagnetic radiation by a free charged particle, as described by classical electromagnetism. It is the low-energy limit of Compton scattering: the particle's kinetic energy and photon frequen ...
*
Resonant magnetic perturbations Resonant magnetic perturbations (RMPs) are a special type of magnetic field perturbations used to control burning plasma instabilities called edge-localized modes (ELMs) in magnetic fusion devices such as tokamaks. The efficiency of RMPs for contr ...
References
External links
Magnetic fusion in the Czech RepublicDiagnostic system on COMPASS
https://iopscience.iop.org/article/10.1088/0741-3335/58/1/014015
{{fusion experiments
Tokamaks
Nuclear technology in the Czech Republic