H-mode access on JET and implications for ITER

Y. Andrew, T.M. Biewer, K. Crombe, D. Keeling, E. de la Luna, C. Giroud, N.C. Hawkes, M. Kempenaars, A. Korotkov, A. Meigs, Y.R. Martin, A. Murari, I. Nunes, R. Sartori, JET EFDA contributors, Tuomas Tala

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Abstract

One of the critical issues for ITER is access to an H-mode regime with good confinement, H98 = 1. The most basic scaling laws for power threshold for the L–H transition, Pth, take the variation with plasma density, magnetic field and plasma size into account. However, the large variations in the Pth data from the values estimated with such simple scaling laws indicate other underlying dependencies. Another important consideration for ITER is that H-modes with higher values of energy confinement factors are often obtained with input power values much greater than Pth. This paper presents results from recent studies on JET to assess possible hidden variables for H-mode access over a wide range of plasma conditions. Experimental results demonstrate that sensitivity to the magnetic shaping and divertor geometry could account for some of the scatter in the international power threshold database. Hysteresis in the L–H transition Pth has been studied in detail for the first time on JET by comparing values of Pth at the forward and back H-mode transitions over a range of densities. The impact of the edge plasma rotation on H-mode access has also been considered on JET with a toroidal field ripple scan across the L–H and H–L transitions. Finally, the total input power required relative to the measured value of Pth for access to a steady-state H-mode with H98 = 1 has been examined for a highly shaped magnetic configuration. The implications of these results for the attainment of H-mode with good confinement on ITER are discussed.
Original languageEnglish
Article number124053
JournalPlasma Physics and Controlled Fusion
Volume50
Issue number12
DOIs
Publication statusPublished - 2008
MoE publication typeA1 Journal article-refereed

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Scaling laws
Plasmas
Plasma density
Hysteresis
scaling laws
Magnetic fields
Geometry
thresholds
ripples
plasma density
hysteresis
sensitivity
geometry
configurations
magnetic fields
energy

Cite this

Andrew, Y., Biewer, T. M., Crombe, K., Keeling, D., de la Luna, E., Giroud, C., ... Tala, T. (2008). H-mode access on JET and implications for ITER. Plasma Physics and Controlled Fusion, 50(12), [124053]. https://doi.org/10.1088/0741-3335/50/12/124053
Andrew, Y. ; Biewer, T.M. ; Crombe, K. ; Keeling, D. ; de la Luna, E. ; Giroud, C. ; Hawkes, N.C. ; Kempenaars, M. ; Korotkov, A. ; Meigs, A. ; Martin, Y.R. ; Murari, A. ; Nunes, I. ; Sartori, R. ; contributors, JET EFDA ; Tala, Tuomas. / H-mode access on JET and implications for ITER. In: Plasma Physics and Controlled Fusion. 2008 ; Vol. 50, No. 12.
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abstract = "One of the critical issues for ITER is access to an H-mode regime with good confinement, H98 = 1. The most basic scaling laws for power threshold for the L–H transition, Pth, take the variation with plasma density, magnetic field and plasma size into account. However, the large variations in the Pth data from the values estimated with such simple scaling laws indicate other underlying dependencies. Another important consideration for ITER is that H-modes with higher values of energy confinement factors are often obtained with input power values much greater than Pth. This paper presents results from recent studies on JET to assess possible hidden variables for H-mode access over a wide range of plasma conditions. Experimental results demonstrate that sensitivity to the magnetic shaping and divertor geometry could account for some of the scatter in the international power threshold database. Hysteresis in the L–H transition Pth has been studied in detail for the first time on JET by comparing values of Pth at the forward and back H-mode transitions over a range of densities. The impact of the edge plasma rotation on H-mode access has also been considered on JET with a toroidal field ripple scan across the L–H and H–L transitions. Finally, the total input power required relative to the measured value of Pth for access to a steady-state H-mode with H98 = 1 has been examined for a highly shaped magnetic configuration. The implications of these results for the attainment of H-mode with good confinement on ITER are discussed.",
author = "Y. Andrew and T.M. Biewer and K. Crombe and D. Keeling and {de la Luna}, E. and C. Giroud and N.C. Hawkes and M. Kempenaars and A. Korotkov and A. Meigs and Y.R. Martin and A. Murari and I. Nunes and R. Sartori and contributors, {JET EFDA} and Tuomas Tala",
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Andrew, Y, Biewer, TM, Crombe, K, Keeling, D, de la Luna, E, Giroud, C, Hawkes, NC, Kempenaars, M, Korotkov, A, Meigs, A, Martin, YR, Murari, A, Nunes, I, Sartori, R, contributors, JETEFDA & Tala, T 2008, 'H-mode access on JET and implications for ITER', Plasma Physics and Controlled Fusion, vol. 50, no. 12, 124053. https://doi.org/10.1088/0741-3335/50/12/124053

H-mode access on JET and implications for ITER. / Andrew, Y.; Biewer, T.M.; Crombe, K.; Keeling, D.; de la Luna, E.; Giroud, C.; Hawkes, N.C.; Kempenaars, M.; Korotkov, A.; Meigs, A.; Martin, Y.R.; Murari, A.; Nunes, I.; Sartori, R.; contributors, JET EFDA; Tala, Tuomas.

In: Plasma Physics and Controlled Fusion, Vol. 50, No. 12, 124053, 2008.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - H-mode access on JET and implications for ITER

AU - Andrew, Y.

AU - Biewer, T.M.

AU - Crombe, K.

AU - Keeling, D.

AU - de la Luna, E.

AU - Giroud, C.

AU - Hawkes, N.C.

AU - Kempenaars, M.

AU - Korotkov, A.

AU - Meigs, A.

AU - Martin, Y.R.

AU - Murari, A.

AU - Nunes, I.

AU - Sartori, R.

AU - contributors, JET EFDA

AU - Tala, Tuomas

PY - 2008

Y1 - 2008

N2 - One of the critical issues for ITER is access to an H-mode regime with good confinement, H98 = 1. The most basic scaling laws for power threshold for the L–H transition, Pth, take the variation with plasma density, magnetic field and plasma size into account. However, the large variations in the Pth data from the values estimated with such simple scaling laws indicate other underlying dependencies. Another important consideration for ITER is that H-modes with higher values of energy confinement factors are often obtained with input power values much greater than Pth. This paper presents results from recent studies on JET to assess possible hidden variables for H-mode access over a wide range of plasma conditions. Experimental results demonstrate that sensitivity to the magnetic shaping and divertor geometry could account for some of the scatter in the international power threshold database. Hysteresis in the L–H transition Pth has been studied in detail for the first time on JET by comparing values of Pth at the forward and back H-mode transitions over a range of densities. The impact of the edge plasma rotation on H-mode access has also been considered on JET with a toroidal field ripple scan across the L–H and H–L transitions. Finally, the total input power required relative to the measured value of Pth for access to a steady-state H-mode with H98 = 1 has been examined for a highly shaped magnetic configuration. The implications of these results for the attainment of H-mode with good confinement on ITER are discussed.

AB - One of the critical issues for ITER is access to an H-mode regime with good confinement, H98 = 1. The most basic scaling laws for power threshold for the L–H transition, Pth, take the variation with plasma density, magnetic field and plasma size into account. However, the large variations in the Pth data from the values estimated with such simple scaling laws indicate other underlying dependencies. Another important consideration for ITER is that H-modes with higher values of energy confinement factors are often obtained with input power values much greater than Pth. This paper presents results from recent studies on JET to assess possible hidden variables for H-mode access over a wide range of plasma conditions. Experimental results demonstrate that sensitivity to the magnetic shaping and divertor geometry could account for some of the scatter in the international power threshold database. Hysteresis in the L–H transition Pth has been studied in detail for the first time on JET by comparing values of Pth at the forward and back H-mode transitions over a range of densities. The impact of the edge plasma rotation on H-mode access has also been considered on JET with a toroidal field ripple scan across the L–H and H–L transitions. Finally, the total input power required relative to the measured value of Pth for access to a steady-state H-mode with H98 = 1 has been examined for a highly shaped magnetic configuration. The implications of these results for the attainment of H-mode with good confinement on ITER are discussed.

U2 - 10.1088/0741-3335/50/12/124053

DO - 10.1088/0741-3335/50/12/124053

M3 - Article

VL - 50

JO - Plasma Physics and Controlled Fusion

JF - Plasma Physics and Controlled Fusion

SN - 0741-3335

IS - 12

M1 - 124053

ER -

Andrew Y, Biewer TM, Crombe K, Keeling D, de la Luna E, Giroud C et al. H-mode access on JET and implications for ITER. Plasma Physics and Controlled Fusion. 2008;50(12). 124053. https://doi.org/10.1088/0741-3335/50/12/124053