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Term Definition
magnetic bottle 1) The containment of a plasma during thermonuclear experiments by applying a specific pattern of magnetic fields. 2) The magnetic field used to confine a plasma in controlled fusion experiments.
magnetic fusion The use of magnetic fields to confine a plasma that is undergoing fusion.
magnetic quench detection A detection system to protect a superconducting magnet from going to its "normal state".
magnetic shear The change in direction of the magnetic field from one nested magnetic surface to another.
magnetohydrodynamic MHD, the study of the motions of an electrically conducting fluid in the presence of a magnetic field. The motion of the fluid gives rise to induced electric currents which interact with the magnetic field which in turn modifies the motion. The phenomenon has applications to magnetic fields in space and and to the possibility of generating electricity.
magnetohydrodynamic instabilities See "kink mode", "pinch effect", and “sawteeth”.
maintainability 1) A system effectiveness concept, measures the ease and rapidity that a system or equipment can be restored to operational status after failing. 2) The probability that an item of hardware or software will be restored to a specific condition within a given period of time.
major plasma radius The centre of the last closed flux surface at the height of the maximum width of the plasma. The major radius of the torus.
MARFE multifaceted asymmetric radiation from the edge of tokamak plasmas
MDAS mass data acquisition system
MDSS mass data storage system
mechanical structure The structure providing external support for the tokamak magnets against electromagnetic and mechanical loads.
metadata Data defining where a data object resides and defining other attributes about the data object (e.g., date of creation or design status).
MHD magnetohydrodynamic
mhd instability Instabilities driven by the energy of the magnetic field and by the momentum of charged particles in the plasma. Small displacements of plasma density from the equilibrium position can reinforce that displacement until a further compensating force counteracts that reinforcement or the plasma equilibrium configuration is disrupted. Various modes of such displacement in the toroidal and poloidal planes can be stabilised so that the bulk plasma remains in position.
microwave scattering and reflectometer A diagnostic system used in tokamaks for fluctuation measurements.
MIG metal in gap
minor plasma radius The small radius of the plasma torus.
Mirnov loops Conducting wire loops used in tokamaks to measure magnetohydrodynamic instabilities.
mockup A piece of hardware reproducing some or all of the features of an actual component to be used in ITER.
model coil Coils used for testing manufacturing processes, using a design exhibiting key features of the ITER magnet coils.
MG motor-generator
monoblock A type of construction of plasma-facing components in which blocks of plasma-facing material are threaded onto coolant pipes through a central hole. A variant is the saddle block, in which the hole intersects the block edge on the side away from the plasma.
monster sawteeth Very large internal magnetohydrodynamic oscillations with sawteeth-like amplitude variations occurring at the centre of a tokamak plasma.
motional Stark effect MSE, a diagnostic system used for measuring the safety factor on axis in a tokamak.
MOU matching optics unit
MSE motional stark effect
MT Magnet Technology Conference
MTBF mean time between failures
MTL main transmission line
MTTR mean time to repair

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  Updated 13 February, 2017