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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DO - 10.1088/1741-4326/ab25cb

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VL - 59

JO - Nuclear Fusion

JF - Nuclear Fusion

SN - 0029-5515

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