Dependence of scrape-off layer profiles and turbulence on gas fuelling in high density H-mode regimes in TCV

A. Stagni; N. Vianello; C. K. Tsui; C. Colandrea; S. Gorno; M. Bernert; J. A. Boedo; D. Brida; G. Falchetto; A. Hakola; G. Harrer; H. Reimerdes; C. Theiler; E. Tsitrone; N. Walkden

doi:10.1088/1741-4326/ac8234

Dependence of scrape-off layer profiles and turbulence on gas fuelling in high density H-mode regimes in TCV

A. Stagni
, N. Vianello
, C. K. Tsui
, C. Colandrea
, S. Gorno
, M. Bernert
, J. A. Boedo
, D. Brida
, G. Falchetto
, A. Hakola
, G. Harrer
, H. Reimerdes
, C. Theiler
, E. Tsitrone
, N. Walkden

Research output: Contribution to journal › Article › peer-review

22 Scopus citations

Abstract

A set of high density, highly shaped H-mode discharges has been performed in the TCV tokamak with the aim of assessing the effects of increasing divertor neutral recycling on the properties of upstream inter-ELM scrape-off layer (SOL) profiles and transport. An increase of divertor neutral pressure has been correlated with the evolution of separatrix properties and turbulence level. The latter has been quantified by means of the α _t parameter introduced in (Eich 2020 Nucl. Fusion 60 056016), describing the contribution of resistive-interchange turbulence in the SOL relative to drift wave transport. The analysis reveals a general broadening of the upstream SOL profiles as α _t increases, with the SOL power width measured by the vertical IR thermography system increasing significantly. In a similar way, the upstream density profile widens in the near SOL, whereas in the far SOL a density shoulder is observed to progressively form and increase in amplitude. This behaviour is associated with an enhancement of far SOL turbulent transport in the form of blob-filaments travelling radially faster across the far SOL and becoming bigger at higher α _t. The detected filaments, evaluated from the fast reciprocating probe at the outer midplane, are determined to mostly belong to the resistive ballooning and resistive X-point regimes.

Original language	English
Article number	096031
Journal	Nuclear Fusion
Volume	62
Issue number	9
DOIs	https://doi.org/10.1088/1741-4326/ac8234
State	Published - Sep 2022
Externally published	Yes

Funding

This work has been carried out within the framework of the EUROfusion Consortium, funded by the European Union via the Euratom Research and Training Programme (Grant Agreement No. 101052200—EUROfusion). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Commission. Neither the European Union nor the European Commission can be held responsible for them. This work was supported in part by the Swiss National Science Foundation and in part by the US Department of Energy under Award No. DE-SC0010529.

Keywords

E-folding lengths
ELMs
H-mode
QCE
blob-filaments
scrape-off layer

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10.1088/1741-4326/ac8234

Cite this

Stagni, A., Vianello, N., Tsui, C. K., Colandrea, C., Gorno, S., Bernert, M., Boedo, J. A., Brida, D., Falchetto, G., Hakola, A., Harrer, G., Reimerdes, H., Theiler, C., Tsitrone, E., & Walkden, N. (2022). Dependence of scrape-off layer profiles and turbulence on gas fuelling in high density H-mode regimes in TCV. Nuclear Fusion, 62(9), Article 096031. https://doi.org/10.1088/1741-4326/ac8234

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title = "Dependence of scrape-off layer profiles and turbulence on gas fuelling in high density H-mode regimes in TCV",

abstract = "A set of high density, highly shaped H-mode discharges has been performed in the TCV tokamak with the aim of assessing the effects of increasing divertor neutral recycling on the properties of upstream inter-ELM scrape-off layer (SOL) profiles and transport. An increase of divertor neutral pressure has been correlated with the evolution of separatrix properties and turbulence level. The latter has been quantified by means of the α t parameter introduced in (Eich 2020 Nucl. Fusion 60 056016), describing the contribution of resistive-interchange turbulence in the SOL relative to drift wave transport. The analysis reveals a general broadening of the upstream SOL profiles as α t increases, with the SOL power width measured by the vertical IR thermography system increasing significantly. In a similar way, the upstream density profile widens in the near SOL, whereas in the far SOL a density shoulder is observed to progressively form and increase in amplitude. This behaviour is associated with an enhancement of far SOL turbulent transport in the form of blob-filaments travelling radially faster across the far SOL and becoming bigger at higher α t. The detected filaments, evaluated from the fast reciprocating probe at the outer midplane, are determined to mostly belong to the resistive ballooning and resistive X-point regimes.",

keywords = "E-folding lengths, ELMs, H-mode, QCE, blob-filaments, scrape-off layer",

author = "A. Stagni and N. Vianello and Tsui, \{C. K.\} and C. Colandrea and S. Gorno and M. Bernert and Boedo, \{J. A.\} and D. Brida and G. Falchetto and A. Hakola and G. Harrer and H. Reimerdes and C. Theiler and E. Tsitrone and N. Walkden",

note = "Publisher Copyright: {\textcopyright} 2022 IAEA, Vienna.",

year = "2022",

month = sep,

doi = "10.1088/1741-4326/ac8234",

language = "English",

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Stagni, A, Vianello, N, Tsui, CK, Colandrea, C, Gorno, S, Bernert, M, Boedo, JA, Brida, D, Falchetto, G, Hakola, A, Harrer, G, Reimerdes, H, Theiler, C, Tsitrone, E & Walkden, N 2022, 'Dependence of scrape-off layer profiles and turbulence on gas fuelling in high density H-mode regimes in TCV', Nuclear Fusion, vol. 62, no. 9, 096031. https://doi.org/10.1088/1741-4326/ac8234

TY - JOUR

T1 - Dependence of scrape-off layer profiles and turbulence on gas fuelling in high density H-mode regimes in TCV

AU - Stagni, A.

AU - Vianello, N.

AU - Tsui, C. K.

AU - Colandrea, C.

AU - Gorno, S.

AU - Bernert, M.

AU - Boedo, J. A.

AU - Brida, D.

AU - Falchetto, G.

AU - Hakola, A.

AU - Harrer, G.

AU - Reimerdes, H.

AU - Theiler, C.

AU - Tsitrone, E.

AU - Walkden, N.

PY - 2022/9

Y1 - 2022/9

N2 - A set of high density, highly shaped H-mode discharges has been performed in the TCV tokamak with the aim of assessing the effects of increasing divertor neutral recycling on the properties of upstream inter-ELM scrape-off layer (SOL) profiles and transport. An increase of divertor neutral pressure has been correlated with the evolution of separatrix properties and turbulence level. The latter has been quantified by means of the α t parameter introduced in (Eich 2020 Nucl. Fusion 60 056016), describing the contribution of resistive-interchange turbulence in the SOL relative to drift wave transport. The analysis reveals a general broadening of the upstream SOL profiles as α t increases, with the SOL power width measured by the vertical IR thermography system increasing significantly. In a similar way, the upstream density profile widens in the near SOL, whereas in the far SOL a density shoulder is observed to progressively form and increase in amplitude. This behaviour is associated with an enhancement of far SOL turbulent transport in the form of blob-filaments travelling radially faster across the far SOL and becoming bigger at higher α t. The detected filaments, evaluated from the fast reciprocating probe at the outer midplane, are determined to mostly belong to the resistive ballooning and resistive X-point regimes.

AB - A set of high density, highly shaped H-mode discharges has been performed in the TCV tokamak with the aim of assessing the effects of increasing divertor neutral recycling on the properties of upstream inter-ELM scrape-off layer (SOL) profiles and transport. An increase of divertor neutral pressure has been correlated with the evolution of separatrix properties and turbulence level. The latter has been quantified by means of the α t parameter introduced in (Eich 2020 Nucl. Fusion 60 056016), describing the contribution of resistive-interchange turbulence in the SOL relative to drift wave transport. The analysis reveals a general broadening of the upstream SOL profiles as α t increases, with the SOL power width measured by the vertical IR thermography system increasing significantly. In a similar way, the upstream density profile widens in the near SOL, whereas in the far SOL a density shoulder is observed to progressively form and increase in amplitude. This behaviour is associated with an enhancement of far SOL turbulent transport in the form of blob-filaments travelling radially faster across the far SOL and becoming bigger at higher α t. The detected filaments, evaluated from the fast reciprocating probe at the outer midplane, are determined to mostly belong to the resistive ballooning and resistive X-point regimes.

KW - E-folding lengths

KW - ELMs

KW - H-mode

KW - QCE

KW - blob-filaments

KW - scrape-off layer

UR - https://www.scopus.com/pages/publications/85136317849

U2 - 10.1088/1741-4326/ac8234

DO - 10.1088/1741-4326/ac8234

M3 - Article

AN - SCOPUS:85136317849

SN - 0029-5515

VL - 62

JO - Nuclear Fusion

JF - Nuclear Fusion

IS - 9

M1 - 096031

ER -

Dependence of scrape-off layer profiles and turbulence on gas fuelling in high density H-mode regimes in TCV

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