Rotary FILD in MAST-U

The Mega Amp Spherical Tokamak (MAST), in United Kingdom, uses lower magnetic fields and a lower aspect ratio to achieve the same plasma pressure, in comparison to conventional tokamaks. MAST is currently being upgraded (MAST-U) to allow for state-of-the-art divertor physics, current drive and ELM stability research. Fast-ion confinement will be crucial to successfully carry out the research plan in MAST-U. For this reason, in the framework of this upgrade, the first FILD for MAST-U has been designed and installed. It is mounted on an axially and angularly actuated mechanism that makes it possible to independently adapt the orientation and radial position of the probe, thus maximizing the detector velocity-space coverage in a broad range of plasma scenarios. Besides, due to the low magnetic field in MAST-U, the fast-ions gyroradius are in the range of 13 cm, requiring a large probe head of 15 cm diameter, which has made it a challenging mechanical design. The MAST-U operation is scheduled to start in 2021.

For more details about the MAST-U FILD see:
[1] J.F. Rivero-Rodriguez et al., A rotary and reciprocating scintillator based fast-ion loss detector for the MAST-U tokamak, Rev. Sci. Instrum. 89, 10I112 (2018).