Metal impurity transport control in JET H-mode plasmas with central ion cyclotron radiofrequency power injection

M. Valisa, L. Carraro, I. Predebon, M.E. Puiatti, C. Angioni, I. Coffey, Carine Giroud, L. Lauro-Taroni, B. Alper, M. Baruzzo, P. Belo Dasilva, P. Buratti, L. Garzotti, D. Van Eester, E. Lerche, P. Mantica, V. Naulin, Tuomas Tala, M. Tsalas

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Abstract

The scan of ion cyclotron resonant heating (ICRH) power has been used to systematically study the pump out effect of central electron heating on impurities such as Ni and Mo in H-mode low collisionality discharges in JET. The transport parameters of Ni and Mo have been measured by introducing a transient perturbation on their densities via the laser blow off technique. Without ICRH Ni and Mo density profiles are typically peaked. The application of ICRH induces on Ni and Mo in the plasma centre (at normalized poloidal flux ρ = 0.2) an outward drift approximately proportional to the amount of injected power. Above a threshold of ICRH power of about 3 MW in the specific case the radial flow of Ni and Mo changes from inwards to outwards and the impurity profiles, extrapolated to stationary conditions, become hollow. At mid-radius the impurity profiles become flat or only slightly hollow. In the plasma centre the variation of the convection-to-diffusivity ratio v/D of Ni is particularly well correlated with the change in the ion temperature gradient in qualitative agreement with the neoclassical theory. However, the experimental radial velocity is larger than the neoclassical one by up to one order of magnitude. Gyrokinetic simulations of the radial impurity fluxes induced by electrostatic turbulence do not foresee a flow reversal in the analysed discharges.

Original languageEnglish
Article number033002
Number of pages11
JournalNuclear Fusion
Volume51
Issue number3
DOIs
Publication statusPublished - 1 Mar 2011
MoE publication typeA1 Journal article-refereed

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cyclotrons
injection
impurities
heating
metals
ions
hollow
profiles
poloidal flux
radial flow
ion temperature
radial velocity
diffusivity
temperature gradients
convection
turbulence
electrostatics
pumps
perturbation
radii

Cite this

Valisa, M., Carraro, L., Predebon, I., Puiatti, M. E., Angioni, C., Coffey, I., ... Tsalas, M. (2011). Metal impurity transport control in JET H-mode plasmas with central ion cyclotron radiofrequency power injection. Nuclear Fusion, 51(3), [033002]. https://doi.org/10.1088/0029-5515/51/3/033002
Valisa, M. ; Carraro, L. ; Predebon, I. ; Puiatti, M.E. ; Angioni, C. ; Coffey, I. ; Giroud, Carine ; Lauro-Taroni, L. ; Alper, B. ; Baruzzo, M. ; Belo Dasilva, P. ; Buratti, P. ; Garzotti, L. ; Van Eester, D. ; Lerche, E. ; Mantica, P. ; Naulin, V. ; Tala, Tuomas ; Tsalas, M. / Metal impurity transport control in JET H-mode plasmas with central ion cyclotron radiofrequency power injection. In: Nuclear Fusion. 2011 ; Vol. 51, No. 3.
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title = "Metal impurity transport control in JET H-mode plasmas with central ion cyclotron radiofrequency power injection",
abstract = "The scan of ion cyclotron resonant heating (ICRH) power has been used to systematically study the pump out effect of central electron heating on impurities such as Ni and Mo in H-mode low collisionality discharges in JET. The transport parameters of Ni and Mo have been measured by introducing a transient perturbation on their densities via the laser blow off technique. Without ICRH Ni and Mo density profiles are typically peaked. The application of ICRH induces on Ni and Mo in the plasma centre (at normalized poloidal flux ρ = 0.2) an outward drift approximately proportional to the amount of injected power. Above a threshold of ICRH power of about 3 MW in the specific case the radial flow of Ni and Mo changes from inwards to outwards and the impurity profiles, extrapolated to stationary conditions, become hollow. At mid-radius the impurity profiles become flat or only slightly hollow. In the plasma centre the variation of the convection-to-diffusivity ratio v/D of Ni is particularly well correlated with the change in the ion temperature gradient in qualitative agreement with the neoclassical theory. However, the experimental radial velocity is larger than the neoclassical one by up to one order of magnitude. Gyrokinetic simulations of the radial impurity fluxes induced by electrostatic turbulence do not foresee a flow reversal in the analysed discharges.",
author = "M. Valisa and L. Carraro and I. Predebon and M.E. Puiatti and C. Angioni and I. Coffey and Carine Giroud and L. Lauro-Taroni and B. Alper and M. Baruzzo and {Belo Dasilva}, P. and P. Buratti and L. Garzotti and {Van Eester}, D. and E. Lerche and P. Mantica and V. Naulin and Tuomas Tala and M. Tsalas",
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Valisa, M, Carraro, L, Predebon, I, Puiatti, ME, Angioni, C, Coffey, I, Giroud, C, Lauro-Taroni, L, Alper, B, Baruzzo, M, Belo Dasilva, P, Buratti, P, Garzotti, L, Van Eester, D, Lerche, E, Mantica, P, Naulin, V, Tala, T & Tsalas, M 2011, 'Metal impurity transport control in JET H-mode plasmas with central ion cyclotron radiofrequency power injection', Nuclear Fusion, vol. 51, no. 3, 033002. https://doi.org/10.1088/0029-5515/51/3/033002

Metal impurity transport control in JET H-mode plasmas with central ion cyclotron radiofrequency power injection. / Valisa, M.; Carraro, L.; Predebon, I.; Puiatti, M.E.; Angioni, C.; Coffey, I.; Giroud, Carine; Lauro-Taroni, L.; Alper, B.; Baruzzo, M.; Belo Dasilva, P.; Buratti, P.; Garzotti, L.; Van Eester, D.; Lerche, E.; Mantica, P.; Naulin, V.; Tala, Tuomas; Tsalas, M.

In: Nuclear Fusion, Vol. 51, No. 3, 033002, 01.03.2011.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Metal impurity transport control in JET H-mode plasmas with central ion cyclotron radiofrequency power injection

AU - Valisa, M.

AU - Carraro, L.

AU - Predebon, I.

AU - Puiatti, M.E.

AU - Angioni, C.

AU - Coffey, I.

AU - Giroud, Carine

AU - Lauro-Taroni, L.

AU - Alper, B.

AU - Baruzzo, M.

AU - Belo Dasilva, P.

AU - Buratti, P.

AU - Garzotti, L.

AU - Van Eester, D.

AU - Lerche, E.

AU - Mantica, P.

AU - Naulin, V.

AU - Tala, Tuomas

AU - Tsalas, M.

PY - 2011/3/1

Y1 - 2011/3/1

N2 - The scan of ion cyclotron resonant heating (ICRH) power has been used to systematically study the pump out effect of central electron heating on impurities such as Ni and Mo in H-mode low collisionality discharges in JET. The transport parameters of Ni and Mo have been measured by introducing a transient perturbation on their densities via the laser blow off technique. Without ICRH Ni and Mo density profiles are typically peaked. The application of ICRH induces on Ni and Mo in the plasma centre (at normalized poloidal flux ρ = 0.2) an outward drift approximately proportional to the amount of injected power. Above a threshold of ICRH power of about 3 MW in the specific case the radial flow of Ni and Mo changes from inwards to outwards and the impurity profiles, extrapolated to stationary conditions, become hollow. At mid-radius the impurity profiles become flat or only slightly hollow. In the plasma centre the variation of the convection-to-diffusivity ratio v/D of Ni is particularly well correlated with the change in the ion temperature gradient in qualitative agreement with the neoclassical theory. However, the experimental radial velocity is larger than the neoclassical one by up to one order of magnitude. Gyrokinetic simulations of the radial impurity fluxes induced by electrostatic turbulence do not foresee a flow reversal in the analysed discharges.

AB - The scan of ion cyclotron resonant heating (ICRH) power has been used to systematically study the pump out effect of central electron heating on impurities such as Ni and Mo in H-mode low collisionality discharges in JET. The transport parameters of Ni and Mo have been measured by introducing a transient perturbation on their densities via the laser blow off technique. Without ICRH Ni and Mo density profiles are typically peaked. The application of ICRH induces on Ni and Mo in the plasma centre (at normalized poloidal flux ρ = 0.2) an outward drift approximately proportional to the amount of injected power. Above a threshold of ICRH power of about 3 MW in the specific case the radial flow of Ni and Mo changes from inwards to outwards and the impurity profiles, extrapolated to stationary conditions, become hollow. At mid-radius the impurity profiles become flat or only slightly hollow. In the plasma centre the variation of the convection-to-diffusivity ratio v/D of Ni is particularly well correlated with the change in the ion temperature gradient in qualitative agreement with the neoclassical theory. However, the experimental radial velocity is larger than the neoclassical one by up to one order of magnitude. Gyrokinetic simulations of the radial impurity fluxes induced by electrostatic turbulence do not foresee a flow reversal in the analysed discharges.

U2 - 10.1088/0029-5515/51/3/033002

DO - 10.1088/0029-5515/51/3/033002

M3 - Article

VL - 51

JO - Nuclear Fusion

JF - Nuclear Fusion

SN - 0029-5515

IS - 3

M1 - 033002

ER -