| 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”. |
| main transmission line | MTL, coaxial line to transport radio frequency power in the use of ion cyclotron radio frequency (ICRF). |
| 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. |
| man-machine interface | The interface (usually in a remote handling system) between the controller and the tool interfacing with the components on the ITER device. It usually attempts to mimic, with scaled-down feedback modelling, the forces that are actually being experienced by the tool. Usually the man-machine interface is an essential element for one-off repair operations where automatic repair is too imprecise, or as a training input mechanism for that automatic repair. |
| MARFE | multifaceted asymmetric radiation from the edge of tokamak plasmas |
| MAST | Mega Amp Spherical Tokamak , Culham Laboratory, UK |
| maximum permissible concentration |
MPC, the amount of radiactive material in air or water that might be expected to result in a maximum permissible dose to persons consuming them at a standard rate of intake. |
| MCNP | Monte Carlo Neutron-Photon (model), a type of code used to study neutron and gamma ray attenuation properties of shielding configurations. It uses a type of probabalistic analysis known as the Monte Carlo technique (essentially a series of trials tracing what happens to individual particles or photons) to determine radiation dose at particular locations. |
| mean absorbed dose |
In a tissue or organ, the energy absorbed per unit mass. The unit is the gray (Gy) = 1 joule/kg = 100 rad. (There is no correction for the biological damage of the radiation.) |
| mechanical alloying | MA, a materials processing method for assembling metal constitutents with a controlled microstructure by repeated welding, fracturing, and rewelding of a mixture of powder particles, generally in a high-energy ball mill. |
| 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). |
| MEXT | Ministry of Education, Culture, Sport, Science and Technology (Japan) |
| 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. |
| minor plasma radius | The small radius of the plasma torus. |
| Mirnov loops | Conducting wire loops used in tokamaks to measure magnetohydrodynamic instabilities. |
| MIT | Massachusetts Institute of Technology, USA |
| 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. |
| module centre post | An earlier version of the blanket module radial support attachment now superseded but characteristic of the attachment now planned to be used. Such attachments are now employed at the four corners of the modules, not at the centre. |
| MOFA | Ministry of Foreign Affairs (Japan) |
| 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. |
| motor control center | MCC, electrical equipment that provides field-level control to energize or operate equipment such as motors, motor-generators, etc. |
| MPC | maximum permissible concentration |
| 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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