Real-time plasma position reflectometry system development and integration on COMPASS tokamak

0534527 - ÚFP 2021 RIV CH eng J - Journal Article
Lourenço, P. D. - Santos, J.M. - Havránek, Aleš - Bogár, Ondrej - Havlíček, Josef - Zajac, Jaromír - Silva, A. - Batista, A.J.N. - Hron, Martin - Pánek, Radomír - Fernandes, H.
Real-time plasma position reflectometry system development and integration on COMPASS tokamak.
Fusion Engineering and Design. Roč. 160, November (2020), č. článku 112017. ISSN 0920-3796. E-ISSN 1873-7196
R&D Projects: GA MŠMT(CZ) LM2015045; GA MŠMT(CZ) EF16_019/0000768
Institutional support: RVO:61389021
Keywords : COMPASS tokamak * Distributed feedback * MARTe framework * Plasma position reflectometry * Real-time
OECD category: Fluids and plasma physics (including surface physics)
Impact factor: 1.453, year: 2020
Method of publishing: Limited access
https://www.sciencedirect.com/science/article/abs/pii/S0920379620305652?via%3Dihub

O-mode frequency-modulated continuous wave (FMCW) reflectometry provides an alternative to magnetic measurements in the determination of the plasma separatrix position for plasma position control. This type of measurement proves to be particularly attractive for the control of future fusion reactors where the harsh radiation environment may damage magnetic probes or induce non-compensable measurement drifts. Plasma position reflectometry (PPR), first demonstrated in ASDEX-Upgrade, is a control technique that is increasingly important to validate in diversified experimental devices and relevant plasma regimes. The COMPASS tokamak provides suitable conditions for such advanced demonstrations and regular PPR operation and development, thanks to its O-mode reflectometer and Multi-Threaded Application Real-Time executor (MARTe) based real-time control system. Herein we present the integration of a PPR system on COMPASS, both at hardware and software levels. Reflectometry swept measurements require signals to be acquired in bursts of data and streamed to the corresponding MARTe-PPR node through PCIe® fibre-optic links. The data transferred in real-time is used to reconstruct the radial density profiles from which the outer separatrix position is estimated. This estimate is then delivered to the central MARTe controller node via a dedicated Xilinx® Aurora® link at a rate matching COMPASS's 500 μs slow control cycle. The implemented system systematically met the required latency specifications, being able to deliver an estimation of the plasma radial position capable of successfully replacing the corresponding magnetic measurements in the plasma position feedback control loops.
Permanent Link: http://hdl.handle.net/11104/0312706