Mega Ampere Spherical Tokamak
Encyclopedia
The Mega Ampere Spherical Tokamak, or MAST experiment is a nuclear fusion
experiment in operation at Culham
, Oxfordshire
, England
since December 1999. It follows the highly successful START
experiment (1991 - 1998). MAST uses the same innovative spherical tokamak
design as START, which has shown itself to be more efficient than the conventional toroidal
design, adopted by JET
and ITER
. START proved to exceed even the most optimistic predictions and the purpose of MAST is to confirm the results of its forerunner by using a larger more purpose-built experiment.
It was fully commissioned by EURATOM/UKAEA and took two years to design and a further two years to construct. It includes a neutral beam injector similar to that used on START and uses the same merging compression technique instead of the conventional direct induction. Merging compression provides a valuable saving of central solenoid flux, which can then be used to further ramp up the plasma current and/or maintain the required current flat-top.
The device is presently planning a major upgrade to significantly enhance its capabilities to address its primary objectives (listed below).
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...
experiment in operation at Culham
Culham
Culham is a village and civil parish on the north bank of the River Thames, just over south of Abingdon in Oxfordshire.-Manor:The toponym comes from the Old English Cula's hamm, referring to the village's position in a bend of the Thames...
, Oxfordshire
Oxfordshire
Oxfordshire is a county in the South East region of England, bordering on Warwickshire and Northamptonshire , Buckinghamshire , Berkshire , Wiltshire and Gloucestershire ....
, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
since December 1999. It follows the highly successful START
Small Tight Aspect Ratio Tokamak
The Small Tight Aspect Ratio Tokamak, or START was a nuclear fusion experiment that used magnetic confinement to hold plasma. The experiment began at the Culham Science Centre in the United Kingdom in 1991 and was retired in 1998. It was built as a low cost design, largely using parts already...
experiment (1991 - 1998). MAST uses the same innovative spherical tokamak
Spherical tokamak
A spherical tokamak is a type of fusion power device based on the tokamak principle. It is notable for its very narrow profile, or "aspect ratio". A traditional tokamak has a toroidal confinement area that gives it an overall shape similar to a donut, complete with a large hole in the middle...
design as START, which has shown itself to be more efficient than the conventional toroidal
Toroid (geometry)
In mathematics, a toroid is a doughnut-shaped object, such as an O-ring. Its annular shape is generated by revolving a plane geometrical figure about an axis external to that figure which is parallel to the plane of the figure and does not intersect the figure...
design, adopted by JET
Joint European Torus
JET, the Joint European Torus, is the largest magnetic confinement plasma physics experiment worldwide currently in operation. Its main purpose is to open the way to future nuclear fusion experimental tokamak reactors such as ITER and :DEMO....
and ITER
ITER
ITER is an international nuclear fusion research and engineering project, which is currently building the world's largest and most advanced experimental tokamak nuclear fusion reactor at Cadarache in the south of France...
. START proved to exceed even the most optimistic predictions and the purpose of MAST is to confirm the results of its forerunner by using a larger more purpose-built experiment.
It was fully commissioned by EURATOM/UKAEA and took two years to design and a further two years to construct. It includes a neutral beam injector similar to that used on START and uses the same merging compression technique instead of the conventional direct induction. Merging compression provides a valuable saving of central solenoid flux, which can then be used to further ramp up the plasma current and/or maintain the required current flat-top.
The device is presently planning a major upgrade to significantly enhance its capabilities to address its primary objectives (listed below).
Objective of MAST
- Studies in a new regime, to provide improved understanding of tokamaks, and improved ITER design (e.g. effects of plasma shaping).
- To investigate the potential of the spherical tokamak route to fusion powerFusion powerFusion 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...
.