Comparison of L-mode regimes with enhanced confinement by impurity seeding in JET and DIII-D

G. L. Jackson; M. Murakami; D. R. Baker; R. Budny; M. Charlet; M. R. DeBaar; P. Dumortier; T. E. Evans; R. J. Groebner; N. C. Hawkes; D. L. Hillis; L. C. Ingesson; E. Joffrin; H. R. Koslowski; K. D. Lawson; G. Maddison; G. R. McKee; A. M. Messiaen; P. Monier-Garbet; M. F.F. Nave; J. Ongena; J. Rapp; F. Sartori; G. M. Staebler; M. Stamp; J. D. Strachan; M. Tokar; B. Unterberg; M. Von Hellerman; M. R. Wade

doi:10.1088/0741-3335/44/9/307

Comparison of L-mode regimes with enhanced confinement by impurity seeding in JET and DIII-D

G. L. Jackson, M. Murakami, D. R. Baker, R. Budny, M. Charlet, M. R. DeBaar, P. Dumortier, T. E. Evans, R. J. Groebner, N. C. Hawkes, D. L. Hillis, L. C. Ingesson, E. Joffrin, H. R. Koslowski, K. D. Lawson, G. Maddison, G. R. McKee, A. M. Messiaen, P. Monier-Garbet, M. F.F. NaveJ. Ongena, J. Rapp, F. Sartori, G. M. Staebler, M. Stamp, J. D. Strachan, M. Tokar, B. Unterberg, M. Von Hellerman, M. R. Wade

Laboratory for Plasma Physics

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Abstract

Impurity seeding in both the Joint European Torus (JET) and DIII-D tokamaks has produced L-mode discharges with confinement enhancements comparable to H-mode and a near doubling of the core ion temperature when compared to similar unseeded discharges. Although Z_eff increases with the neon injection, the total neutron rate is as high, or higher, than reference discharges and the calculated thermal neutron rate increases dramatically in both devices. Modelling with the gyrokinetic simulation code shows a reduction in low k turbulence growth rates with neon injection decreasing to less than the E × B shearing rate, consistent with stabilization of ion temperature gradient modes in both JET and DIII-D. Reductions in ion thermal diffusivity are also observed with impurity seeding. Neoclassical m/n = 3/2 tearing modes limit the duration of best performance in DIII-D with neon injection, while n = 1 and n = 2 magnetohydrodynamic modes limit the performance in JET.

Original language	English
Pages (from-to)	1893-1902
Number of pages	10
Journal	Plasma Physics and Controlled Fusion
Volume	44
Issue number	9
DOIs	https://doi.org/10.1088/0741-3335/44/9/307
Publication status	Published - Sept 2002

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Jackson, G. L., Murakami, M., Baker, D. R., Budny, R., Charlet, M., DeBaar, M. R., Dumortier, P., Evans, T. E., Groebner, R. J., Hawkes, N. C., Hillis, D. L., Ingesson, L. C., Joffrin, E., Koslowski, H. R., Lawson, K. D., Maddison, G., McKee, G. R., Messiaen, A. M., Monier-Garbet, P., ... Wade, M. R. (2002). Comparison of L-mode regimes with enhanced confinement by impurity seeding in JET and DIII-D. Plasma Physics and Controlled Fusion, 44(9), 1893-1902. https://doi.org/10.1088/0741-3335/44/9/307

@article{009c31c841174d6ca7b2a8b60b93774c,

title = "Comparison of L-mode regimes with enhanced confinement by impurity seeding in JET and DIII-D",

abstract = "Impurity seeding in both the Joint European Torus (JET) and DIII-D tokamaks has produced L-mode discharges with confinement enhancements comparable to H-mode and a near doubling of the core ion temperature when compared to similar unseeded discharges. Although Zeff increases with the neon injection, the total neutron rate is as high, or higher, than reference discharges and the calculated thermal neutron rate increases dramatically in both devices. Modelling with the gyrokinetic simulation code shows a reduction in low k turbulence growth rates with neon injection decreasing to less than the E × B shearing rate, consistent with stabilization of ion temperature gradient modes in both JET and DIII-D. Reductions in ion thermal diffusivity are also observed with impurity seeding. Neoclassical m/n = 3/2 tearing modes limit the duration of best performance in DIII-D with neon injection, while n = 1 and n = 2 magnetohydrodynamic modes limit the performance in JET.",

author = "Jackson, {G. L.} and M. Murakami and Baker, {D. R.} and R. Budny and M. Charlet and DeBaar, {M. R.} and P. Dumortier and Evans, {T. E.} and Groebner, {R. J.} and Hawkes, {N. C.} and Hillis, {D. L.} and Ingesson, {L. C.} and E. Joffrin and Koslowski, {H. R.} and Lawson, {K. D.} and G. Maddison and McKee, {G. R.} and Messiaen, {A. M.} and P. Monier-Garbet and Nave, {M. F.F.} and J. Ongena and J. Rapp and F. Sartori and Staebler, {G. M.} and M. Stamp and Strachan, {J. D.} and M. Tokar and B. Unterberg and {Von Hellerman}, M. and Wade, {M. R.}",

year = "2002",

month = sep,

doi = "10.1088/0741-3335/44/9/307",

language = "English",

volume = "44",

pages = "1893--1902",

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Jackson, GL, Murakami, M, Baker, DR, Budny, R, Charlet, M, DeBaar, MR, Dumortier, P, Evans, TE, Groebner, RJ, Hawkes, NC, Hillis, DL, Ingesson, LC, Joffrin, E, Koslowski, HR, Lawson, KD, Maddison, G, McKee, GR, Messiaen, AM, Monier-Garbet, P, Nave, MFF, Ongena, J, Rapp, J, Sartori, F, Staebler, GM, Stamp, M, Strachan, JD, Tokar, M, Unterberg, B, Von Hellerman, M & Wade, MR 2002, 'Comparison of L-mode regimes with enhanced confinement by impurity seeding in JET and DIII-D', Plasma Physics and Controlled Fusion, vol. 44, no. 9, pp. 1893-1902. https://doi.org/10.1088/0741-3335/44/9/307

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T1 - Comparison of L-mode regimes with enhanced confinement by impurity seeding in JET and DIII-D

AU - Jackson, G. L.

AU - Murakami, M.

AU - Baker, D. R.

AU - Budny, R.

AU - Charlet, M.

AU - DeBaar, M. R.

AU - Dumortier, P.

AU - Evans, T. E.

AU - Groebner, R. J.

AU - Hawkes, N. C.

AU - Hillis, D. L.

AU - Ingesson, L. C.

AU - Joffrin, E.

AU - Koslowski, H. R.

AU - Lawson, K. D.

AU - Maddison, G.

AU - McKee, G. R.

AU - Messiaen, A. M.

AU - Monier-Garbet, P.

AU - Nave, M. F.F.

AU - Ongena, J.

AU - Rapp, J.

AU - Sartori, F.

AU - Staebler, G. M.

AU - Stamp, M.

AU - Strachan, J. D.

AU - Tokar, M.

AU - Unterberg, B.

AU - Von Hellerman, M.

AU - Wade, M. R.

PY - 2002/9

Y1 - 2002/9

N2 - Impurity seeding in both the Joint European Torus (JET) and DIII-D tokamaks has produced L-mode discharges with confinement enhancements comparable to H-mode and a near doubling of the core ion temperature when compared to similar unseeded discharges. Although Zeff increases with the neon injection, the total neutron rate is as high, or higher, than reference discharges and the calculated thermal neutron rate increases dramatically in both devices. Modelling with the gyrokinetic simulation code shows a reduction in low k turbulence growth rates with neon injection decreasing to less than the E × B shearing rate, consistent with stabilization of ion temperature gradient modes in both JET and DIII-D. Reductions in ion thermal diffusivity are also observed with impurity seeding. Neoclassical m/n = 3/2 tearing modes limit the duration of best performance in DIII-D with neon injection, while n = 1 and n = 2 magnetohydrodynamic modes limit the performance in JET.

AB - Impurity seeding in both the Joint European Torus (JET) and DIII-D tokamaks has produced L-mode discharges with confinement enhancements comparable to H-mode and a near doubling of the core ion temperature when compared to similar unseeded discharges. Although Zeff increases with the neon injection, the total neutron rate is as high, or higher, than reference discharges and the calculated thermal neutron rate increases dramatically in both devices. Modelling with the gyrokinetic simulation code shows a reduction in low k turbulence growth rates with neon injection decreasing to less than the E × B shearing rate, consistent with stabilization of ion temperature gradient modes in both JET and DIII-D. Reductions in ion thermal diffusivity are also observed with impurity seeding. Neoclassical m/n = 3/2 tearing modes limit the duration of best performance in DIII-D with neon injection, while n = 1 and n = 2 magnetohydrodynamic modes limit the performance in JET.

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U2 - 10.1088/0741-3335/44/9/307

DO - 10.1088/0741-3335/44/9/307

M3 - Article

AN - SCOPUS:0036752101

SN - 0741-3335

VL - 44

SP - 1893

EP - 1902

JO - Plasma Physics and Controlled Fusion

JF - Plasma Physics and Controlled Fusion

IS - 9

ER -

Comparison of L-mode regimes with enhanced confinement by impurity seeding in JET and DIII-D

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