Physics research on the TCV tokamak facility: from conventional to alternative scenarios and beyond

Research output: Contribution to journalArticle

Researchers

Research units

  • Swiss Federal Institute of Technology Lausanne
  • Consorzio RFX
  • Univ Napoli Federico II, University of Naples Federico II, Consorzio CREATE
  • CNR, Istituto Fisica del Plasma "Piero Caldirola" (IFP-CNR), Consiglio Nazionale delle Ricerche (CNR), Ist Fis Plasma
  • Univ Durham, Durham University, Dept Phys
  • Univ Napoli Parthenope, Parthenope University Naples, Consorzio CREATE
  • ITER Org
  • Univ Seville, University of Sevilla, Dept Mech Engn & Mfg
  • Natl Sci Ctr, Kharkov Institute of Physics & Technology, Kharkov Inst Phys & Technol, Inst Plasma Phys
  • Max Planck Inst Plasma Phys, Max Planck Society
  • Eindhoven Univ Technol, Eindhoven University of Technology
  • Univ Calif San Diego, University of California System, University of California San Diego, Ctr Energy Res
  • CAS, Czech Academy of Sciences, Institute of Plasma Physics of the Czech Academy of Sciences, Inst Plasma Phys
  • ENEA CR Frascati, Italian National Agency New Technical Energy & Sustainable Economics Development, Unita Tecn Fus
  • Univ Milano Bicocca, University of Milano-Bicocca, Dept Phys G Occhialini
  • IRFM-CEA
  • Univ York, University of York - UK, York Plasma Inst, Dept Phys
  • Assoc EURATOM Belgian State Lab Plasma Phys, Koninklijke Mil Sch, Ecole Royale Mil
  • Univ Tuscia, Tuscia University, Dept Econ Engn Soc & Business Org DEIm
  • Univ Roma Tor Vergata, University of Rome Tor Vergata, Dept Ind Engn
  • Aix Marseille Univ, Aix-Marseille Universite, Centre National de la Recherche Scientifique (CNRS), CNRS - Institute for Engineering & Systems Sciences (INSIS), CNRS, PIIM UMR7345
  • Culham Sci Ctr, Culham Science Centre, CCFE
  • Inst Plasma Phys & Laser Microfus, Institute of Plasma Physics & Laser Microfusion (IFPiLM)
  • VTT Tech Res Ctr Finland Ltd, VTT Technical Research Center Finland, QTF Ctr Excellence
  • Aalto Univ, Aalto University, Dept Appl Phys, HYBER Ctr Excellence
  • Univ Innsbruck, University of Innsbruck, Inst Ionen & Angew Phys

Abstract

The research program of the TCV tokamak ranges from conventional to advanced-tokamak scenarios and alternative divertor configurations, to exploratory plasmas driven by theoretical insight, exploiting the device's unique shaping capabilities. Disruption avoidance by real-time locked mode prevention or unlocking with electron-cyclotron resonance heating (ECRH) was thoroughly documented, using magnetic and radiation triggers. Runaway generation with high-Z noble-gas injection and runaway dissipation by subsequent Ne or Ar injection were studied for model validation. The new 1 MW neutral beam injector has expanded the parameter range, now encompassing ELMy H-modes in an ITER-like shape and nearly noninductive II-mode discharges sustained by electron cyclotron and neutral beam current drive. In the H-mode, the pedestal pressure increases modestly with nitrogen seeding while fueling moves the density pedestal outwards, but the plasma stored energy is largely uncorrelated to either seeding or fueling. High fueling at high triangularity is key to accessing the attractive small edge-localized mode (type-II) regime. Turbulence is reduced in the core at negative triangularity, consistent with increased confinement and in accord with global gyrokinetic simulations. The geodesic acoustic mode, possibly coupled with avalanche events, has been linked with particle flow to the wall in diverted plasmas. Detachment, scrape-off layer transport, and turbulence were studied in L- and H-modes in both standard and alternative configurations (snowflake, super-X, and beyond). The detachment process is caused by power `starvation' reducing the ionization source, with volume recombination playing only a minor role. Partial detachment in the H-mode is obtained with impurity seeding and has shown little dependence on flux expansion in standard single-null geometry. In the attached 1,-mode phase, increasing the outer connection length reduces the in-out heat-flow asymmetry. A doublet plasma, featuring an internal X-point, was achieved successfully, and a transport barrier was observed in the mantle just outside the internal separatrix. In the near future variableconfiguration baffles and possibly divertor ptunping will be introduced to investigate the effect of divertor closure on exhaust and performance, and 3.5 MW ECR and 1 MW neutral beam injection heating will be added.

Details

Original languageEnglish
Article number112023
Number of pages17
JournalNuclear Fusion
Volume59
Issue number11
Publication statusPublished - Nov 2019
MoE publication typeA1 Journal article-refereed

    Research areas

  • nuclear fusion, tokamak, overview, TCV, MST1, EUROfusion, CONTROL-SYSTEM, PLASMA, CONFINEMENT, DETACHMENT, UPGRADE

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