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@ARTICLE{Gonalves:1007470,
      author       = {Gonçalves, Bruno and Varela, Paulo and Silva, António and
                      Silva, Filipe and Santos, Jorge and Ricardo, Emanuel and
                      Vale, Alberto and Luís, Raúl and Nietiadi, Yohanes and
                      Malaquias, Artur and Belo, Jorge and Dias, José and
                      Ferreira, Jorge and Franke, Thomas and Biel, Wolfgang and
                      Heuraux, Stéphane and Ribeiro, Tiago and De Masi, Gianluca
                      and Tudisco, Onofrio and Cavazzana, Roberto and Marchiori,
                      Giuseppe and D’Arcangelo, Ocleto},
      title        = {{A}dvances, {C}hallenges, and {F}uture {P}erspectives of
                      {M}icrowave {R}eflectometry for {P}lasma {P}osition and
                      {S}hape {C}ontrol on {F}uture {N}uclear {F}usion {D}evices},
      journal      = {Sensors},
      volume       = {23},
      number       = {8},
      issn         = {1424-8220},
      address      = {Basel},
      publisher    = {MDPI},
      reportid     = {FZJ-2023-02070},
      pages        = {3926 -},
      year         = {2023},
      abstract     = {Providing energy from fusion and finding ways to scale up
                      the fusion process to commercial proportions in an
                      efficient, economical, and environmentally benign way is one
                      of the grand challenges for engineering. Controlling the
                      burning plasma in real-time is one of the critical issues
                      that need to be addressed. Plasma Position Reflectometry
                      (PPR) is expected to have an important role in
                      next-generation fusion machines, such as DEMO, as a
                      diagnostic to monitor the position and shape of the plasma
                      continuously, complementing magnetic diagnostics. The
                      reflectometry diagnostic uses radar science methods in the
                      microwave and millimetre wave frequency ranges and is
                      envisaged to measure the radial edge density profile at
                      several poloidal angles providing data for the feedback
                      control of the plasma position and shape. While significant
                      steps have already been given to accomplish that goal, with
                      proof of concept tested first in ASDEX-Upgrade and afterward
                      in COMPASS, important, ground-breaking work is still
                      ongoing. The Divertor Test Tokamak (DTT) facility presents
                      itself as the appropriate future fusion device to implement,
                      develop, and test a PPR system, thus contributing to
                      building a knowledge database in plasma position
                      reflectometry required for its application in DEMO. At DEMO,
                      the PPR diagnostic’s in-vessel antennas and waveguides, as
                      well as the magnetic diagnostics, may be exposed to neutron
                      irradiation fluences 5 to 50 times greater than those
                      experienced by ITER. In the event of failure of either the
                      magnetic or microwave diagnostics, the equilibrium control
                      of the DEMO plasma may be jeopardized. It is, therefore,
                      imperative to ensure that these systems are designed in such
                      a way that they can be replaced if necessary. To perform
                      reflectometry measurements at the 16 envisaged poloidal
                      locations in DEMO, plasma-facing antennas and waveguides are
                      needed to route the microwaves between the plasma through
                      the DEMO upper ports (UPs) to the diagnostic hall. The main
                      integration approach for this diagnostic is to incorporate
                      these groups of antennas and waveguides into a diagnostics
                      slim cassette (DSC), which is a dedicated complete poloidal
                      segment specifically designed to be integrated with the
                      water-cooled lithium lead (WCLL) breeding blanket system.
                      This contribution presents the multiple engineering and
                      physics challenges addressed while designing reflectometry
                      diagnostics using radio science techniques. Namely,
                      short-range dedicated radars for plasma position and shape
                      control in future fusion experiments, the advances enabled
                      by the designs for ITER and DEMO, and the future
                      perspectives. One key development is in electronics, aiming
                      at an advanced compact coherent fast frequency sweeping RF
                      back-end [23–100 GHz in few μs] that is being developed
                      at IPFN-IST using commercial Monolithic Microwave Integrated
                      Circuits (MMIC). The compactness of this back-end design is
                      crucial for the successful integration of many measurement
                      channels in the reduced space available in future fusion
                      machines. Prototype tests of these devices are foreseen to
                      be performed in current nuclear fusion machines.},
      cin          = {IEK-4},
      ddc          = {620},
      cid          = {I:(DE-Juel1)IEK-4-20101013},
      pnm          = {134 - Plasma-Wand-Wechselwirkung (POF4-134)},
      pid          = {G:(DE-HGF)POF4-134},
      typ          = {PUB:(DE-HGF)16},
      pubmed       = {37112274},
      UT           = {WOS:000979130600001},
      doi          = {10.3390/s23083926},
      url          = {https://juser.fz-juelich.de/record/1007470},
}