View in EDS

The updated ITPA global H-mode confinement database: description and analysis.

Saved in:
Bibliographic Details
Title: The updated ITPA global H-mode confinement database: description and analysis.
Authors: Verdoolaege, G. (AUTHOR), Kaye, S.M. (AUTHOR), Angioni, C. (AUTHOR), Kardaun, O.J.W.F. (AUTHOR), Maslov, M. (AUTHOR), Romanelli, M. (AUTHOR), Ryter, F. (AUTHOR), Thomsen, K. (AUTHOR), Team, the ASDEX Upgrade (AUTHOR), Team, the EUROfusion MST1 (AUTHOR), Contributors, JET (AUTHOR)
Source: Nuclear Fusion. Jul2021, Vol. 61 Issue 7, p1-29. 29p.
Subjects: Sparsely populated areas, H-mode plasma confinement, Atomic mass, Tokamaks, Plasma density, Extrapolation, Plasma confinement, Power law (Mathematics)
Abstract: The multi-machine International Tokamak Physics Activity (ITPA) Global H-mode Confinement Database has been upgraded with new data from JET with the ITER-like wall and ASDEX Upgrade with the full tungsten wall. This paper describes the new database and presents results of regression analysis to estimate the global energy confinement scaling in H-mode plasmas using a standard power law. Various subsets of the database are considered, focusing on type of wall and divertor materials, confinement regime (all H-modes, ELMy H or ELM-free) and ITER-like constraints. Apart from ordinary least squares (OLS), two other, robust regression techniques are applied, which take into account uncertainty on all variables. Regression on data from individual devices shows that, generally, the confinement dependence on density and the power degradation are weakest in the fully metallic devices. Using the multi-machine scalings, predictions are made of the confinement time in a standard ELMy H-mode scenario in ITER. The uncertainty on the scaling parameters is discussed with a view to practically useful error bars on the parameters and predictions. One of the derived scalings for ELMy H-modes on an ITER-like subset is studied in particular and compared to the IPB98(y, 2) confinement scaling in engineering and dimensionless form. Transformation of this new scaling from engineering variables to dimensionless quantities is shown to result in large error bars on the dimensionless scaling. Regression analysis in the space of dimensionless variables is therefore proposed as an alternative, yielding acceptable estimates for the dimensionless scaling. The new scaling, which is dimensionally correct within the uncertainties, suggests that some dependencies of confinement in the multi-machine database can be reconciled with parameter scans in individual devices. This includes vanishingly small dependence of confinement on line-averaged density and normalized plasma pressure (β), as well as a noticeable, positive dependence on effective atomic mass and plasma triangularity. Extrapolation of this scaling to ITER yields a somewhat lower confinement time compared to the IPB98(y, 2) prediction, possibly related to the considerably weaker dependence on major radius in the new scaling (slightly above linear). Further studies are needed to compare more flexible regression models with the power law used here. In addition, data from more devices concerning possible 'hidden variables' could help to determine their influence on confinement, while adding data in sparsely populated areas of the parameter space may contribute to further disentangling some of the global confinement dependencies in tokamak plasmas. [ABSTRACT FROM AUTHOR]
Copyright of Nuclear Fusion is the property of IOP Publishing and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Engineering Source
FullText Text:
  Availability: 0
Header DbId: egs
DbLabel: Engineering Source
An: 152025214
AccessLevel: 6
PubType: Academic Journal
PubTypeId: academicJournal
PreciseRelevancyScore: 0
IllustrationInfo
Items – Name: Title
  Label: Title
  Group: Ti
  Data: The updated ITPA global H-mode confinement database: description and analysis.
– Name: Author
  Label: Authors
  Group: Au
  Data: <searchLink fieldCode="AR" term="%22Verdoolaege%2C+G%2E%22">Verdoolaege, G.</searchLink> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Kaye%2C+S%2EM%2E%22">Kaye, S.M.</searchLink> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Angioni%2C+C%2E%22">Angioni, C.</searchLink> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Kardaun%2C+O%2EJ%2EW%2EF%2E%22">Kardaun, O.J.W.F.</searchLink> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Maslov%2C+M%2E%22">Maslov, M.</searchLink> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Romanelli%2C+M%2E%22">Romanelli, M.</searchLink> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Ryter%2C+F%2E%22">Ryter, F.</searchLink> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Thomsen%2C+K%2E%22">Thomsen, K.</searchLink> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Team%2C+the+ASDEX+Upgrade%22">Team, the ASDEX Upgrade</searchLink> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Team%2C+the+EUROfusion+MST1%22">Team, the EUROfusion MST1</searchLink> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Contributors%2C+JET%22">Contributors, JET</searchLink> (AUTHOR)
– Name: TitleSource
  Label: Source
  Group: Src
  Data: <searchLink fieldCode="JN" term="%22Nuclear+Fusion%22">Nuclear Fusion</searchLink>. Jul2021, Vol. 61 Issue 7, p1-29. 29p.
– Name: Subject
  Label: Subjects
  Group: Su
  Data: <searchLink fieldCode="DE" term="%22Sparsely+populated+areas%22">Sparsely populated areas</searchLink><br /><searchLink fieldCode="DE" term="%22H-mode+plasma+confinement%22">H-mode plasma confinement</searchLink><br /><searchLink fieldCode="DE" term="%22Atomic+mass%22">Atomic mass</searchLink><br /><searchLink fieldCode="DE" term="%22Tokamaks%22">Tokamaks</searchLink><br /><searchLink fieldCode="DE" term="%22Plasma+density%22">Plasma density</searchLink><br /><searchLink fieldCode="DE" term="%22Extrapolation%22">Extrapolation</searchLink><br /><searchLink fieldCode="DE" term="%22Plasma+confinement%22">Plasma confinement</searchLink><br /><searchLink fieldCode="DE" term="%22Power+law+%28Mathematics%29%22">Power law (Mathematics)</searchLink>
– Name: Abstract
  Label: Abstract
  Group: Ab
  Data: The multi-machine International Tokamak Physics Activity (ITPA) Global H-mode Confinement Database has been upgraded with new data from JET with the ITER-like wall and ASDEX Upgrade with the full tungsten wall. This paper describes the new database and presents results of regression analysis to estimate the global energy confinement scaling in H-mode plasmas using a standard power law. Various subsets of the database are considered, focusing on type of wall and divertor materials, confinement regime (all H-modes, ELMy H or ELM-free) and ITER-like constraints. Apart from ordinary least squares (OLS), two other, robust regression techniques are applied, which take into account uncertainty on all variables. Regression on data from individual devices shows that, generally, the confinement dependence on density and the power degradation are weakest in the fully metallic devices. Using the multi-machine scalings, predictions are made of the confinement time in a standard ELMy H-mode scenario in ITER. The uncertainty on the scaling parameters is discussed with a view to practically useful error bars on the parameters and predictions. One of the derived scalings for ELMy H-modes on an ITER-like subset is studied in particular and compared to the IPB98(y, 2) confinement scaling in engineering and dimensionless form. Transformation of this new scaling from engineering variables to dimensionless quantities is shown to result in large error bars on the dimensionless scaling. Regression analysis in the space of dimensionless variables is therefore proposed as an alternative, yielding acceptable estimates for the dimensionless scaling. The new scaling, which is dimensionally correct within the uncertainties, suggests that some dependencies of confinement in the multi-machine database can be reconciled with parameter scans in individual devices. This includes vanishingly small dependence of confinement on line-averaged density and normalized plasma pressure (β), as well as a noticeable, positive dependence on effective atomic mass and plasma triangularity. Extrapolation of this scaling to ITER yields a somewhat lower confinement time compared to the IPB98(y, 2) prediction, possibly related to the considerably weaker dependence on major radius in the new scaling (slightly above linear). Further studies are needed to compare more flexible regression models with the power law used here. In addition, data from more devices concerning possible 'hidden variables' could help to determine their influence on confinement, while adding data in sparsely populated areas of the parameter space may contribute to further disentangling some of the global confinement dependencies in tokamak plasmas. [ABSTRACT FROM AUTHOR]
– Name: AbstractSuppliedCopyright
  Label:
  Group: Ab
  Data: <i>Copyright of Nuclear Fusion is the property of IOP Publishing and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.)
PLink https://search.ebscohost.com/login.aspx?direct=true&site=eds-live&db=egs&AN=152025214
RecordInfo BibRecord:
  BibEntity:
    Identifiers:
      – Type: doi
        Value: 10.1088/1741-4326/abdb91
    Languages:
      – Code: eng
        Text: English
    PhysicalDescription:
      Pagination:
        PageCount: 29
        StartPage: 1
    Subjects:
      – SubjectFull: Sparsely populated areas
        Type: general
      – SubjectFull: H-mode plasma confinement
        Type: general
      – SubjectFull: Atomic mass
        Type: general
      – SubjectFull: Tokamaks
        Type: general
      – SubjectFull: Plasma density
        Type: general
      – SubjectFull: Extrapolation
        Type: general
      – SubjectFull: Plasma confinement
        Type: general
      – SubjectFull: Power law (Mathematics)
        Type: general
    Titles:
      – TitleFull: The updated ITPA global H-mode confinement database: description and analysis.
        Type: main
  BibRelationships:
    HasContributorRelationships:
      – PersonEntity:
          Name:
            NameFull: Verdoolaege, G.
      – PersonEntity:
          Name:
            NameFull: Kaye, S.M.
      – PersonEntity:
          Name:
            NameFull: Angioni, C.
      – PersonEntity:
          Name:
            NameFull: Kardaun, O.J.W.F.
      – PersonEntity:
          Name:
            NameFull: Maslov, M.
      – PersonEntity:
          Name:
            NameFull: Romanelli, M.
      – PersonEntity:
          Name:
            NameFull: Ryter, F.
      – PersonEntity:
          Name:
            NameFull: Thomsen, K.
      – PersonEntity:
          Name:
            NameFull: Team, the ASDEX Upgrade
      – PersonEntity:
          Name:
            NameFull: Team, the EUROfusion MST1
      – PersonEntity:
          Name:
            NameFull: Contributors, JET
    IsPartOfRelationships:
      – BibEntity:
          Dates:
            – D: 01
              M: 07
              Text: Jul2021
              Type: published
              Y: 2021
          Identifiers:
            – Type: issn-print
              Value: 00295515
          Numbering:
            – Type: volume
              Value: 61
            – Type: issue
              Value: 7
          Titles:
            – TitleFull: Nuclear Fusion
              Type: main
ResultId 1