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

S. Coda (Corresponding Author), A. Hakola, A. Salmi, T. Tala, , et al.

    Research output: Contribution to journalArticleScientificpeer-review

    3 Citations (Scopus)

    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 non-inductive H-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 L-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 variable-configuration baffles and possibly divertor pumping will be introduced to investigate the effect of divertor closure on exhaust and performance, and 3.5 MW ECRH and 1 MW neutral beam injection heating will be added.

    Original languageEnglish
    Article number112023
    JournalNuclear Fusion
    Volume59
    Issue number11
    DOIs
    Publication statusPublished - 30 Aug 2019
    MoE publication typeA1 Journal article-refereed

    Fingerprint

    physics
    refueling
    neutral beams
    inoculation
    detachment
    electron cyclotron resonance
    heating
    configurations
    turbulence
    gas injection
    baffles
    beam injection
    avoidance
    beam currents
    injectors
    heat transmission
    avalanches
    coupled modes
    closures
    cyclotrons

    Keywords

    • EUROfusion
    • nuclear fusion
    • overview
    • TCV, MST1
    • tokamak

    Cite this

    @article{2b04f0e99b81400baf1f9448d58ddb47,
    title = "Physics research on the TCV tokamak facility: From conventional to alternative scenarios and beyond",
    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 non-inductive H-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 L-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 variable-configuration baffles and possibly divertor pumping will be introduced to investigate the effect of divertor closure on exhaust and performance, and 3.5 MW ECRH and 1 MW neutral beam injection heating will be added.",
    keywords = "EUROfusion, nuclear fusion, overview, TCV, MST1, tokamak",
    author = "S. Coda and M. Agostini and R. Albanese and S. Alberti and E. Alessi and S. Allan and J. Allcock and R. Ambrosino and H. Anand and Y. Andrebe and H. Arnichand and F. Auriemma and Ayllon-Guerola, {J. M.} and F. Bagnato and J. Ball and M. Baquero-Ruiz and Beletskii, {A. A.} and M. Bernert and W. Bin and P. Blanchard and Blanken, {T. C.} and Boedo, {J. A.} and O. Bogar and T. Bolzonella and F. Bombarda and N. Bonanomi and F. Bouquey and C. Bowman and D. Brida and J. Bucalossi and J. Buermans and H. Bufferand and P. Buratti and G. Calabr{\'o} and L. Calacci and Y. Camenen and D. Carnevale and F. Carpanese and M. Carr and L. Carraro and A. Casolari and F. Causa and J. Čeřovsk{\'y} and O. Chella{\"i} and P. Chmielewski and D. Choi and N. Christen and A. Hakola and A. Salmi and T. Tala and {et al.}",
    year = "2019",
    month = "8",
    day = "30",
    doi = "10.1088/1741-4326/ab25cb",
    language = "English",
    volume = "59",
    journal = "Nuclear Fusion",
    issn = "0029-5515",
    publisher = "Institute of Physics IOP",
    number = "11",

    }

    Physics research on the TCV tokamak facility : From conventional to alternative scenarios and beyond. / Coda, S. (Corresponding Author); Hakola, A.; Salmi, A.; Tala, T.; et al.

    In: Nuclear Fusion, Vol. 59, No. 11, 112023, 30.08.2019.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

    T1 - Physics research on the TCV tokamak facility

    T2 - From conventional to alternative scenarios and beyond

    AU - Coda, S.

    AU - Agostini, M.

    AU - Albanese, R.

    AU - Alberti, S.

    AU - Alessi, E.

    AU - Allan, S.

    AU - Allcock, J.

    AU - Ambrosino, R.

    AU - Anand, H.

    AU - Andrebe, Y.

    AU - Arnichand, H.

    AU - Auriemma, F.

    AU - Ayllon-Guerola, J. M.

    AU - Bagnato, F.

    AU - Ball, J.

    AU - Baquero-Ruiz, M.

    AU - Beletskii, A. A.

    AU - Bernert, M.

    AU - Bin, W.

    AU - Blanchard, P.

    AU - Blanken, T. C.

    AU - Boedo, J. A.

    AU - Bogar, O.

    AU - Bolzonella, T.

    AU - Bombarda, F.

    AU - Bonanomi, N.

    AU - Bouquey, F.

    AU - Bowman, C.

    AU - Brida, D.

    AU - Bucalossi, J.

    AU - Buermans, J.

    AU - Bufferand, H.

    AU - Buratti, P.

    AU - Calabró, G.

    AU - Calacci, L.

    AU - Camenen, Y.

    AU - Carnevale, D.

    AU - Carpanese, F.

    AU - Carr, M.

    AU - Carraro, L.

    AU - Casolari, A.

    AU - Causa, F.

    AU - Čeřovský, J.

    AU - Chellaï, O.

    AU - Chmielewski, P.

    AU - Choi, D.

    AU - Christen, N.

    AU - Hakola, A.

    AU - Salmi, A.

    AU - Tala, T.

    AU - et al.,

    PY - 2019/8/30

    Y1 - 2019/8/30

    N2 - 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 non-inductive H-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 L-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 variable-configuration baffles and possibly divertor pumping will be introduced to investigate the effect of divertor closure on exhaust and performance, and 3.5 MW ECRH and 1 MW neutral beam injection heating will be added.

    AB - 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 non-inductive H-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 L-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 variable-configuration baffles and possibly divertor pumping will be introduced to investigate the effect of divertor closure on exhaust and performance, and 3.5 MW ECRH and 1 MW neutral beam injection heating will be added.

    KW - EUROfusion

    KW - nuclear fusion

    KW - overview

    KW - TCV, MST1

    KW - tokamak

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