# NBI Modulation Experiments to Study Momentum Transport and Magnetic Field Induced Ripple Torque on JET

Tuomas Tala, Antti Salmi, P. Mantica, C. Angioni, G Corrigan, P.C. de Vries, C. Giroud, J. Ferreira, J. Lönnroth, V. Naulin, A.G. Peeters, W. Solomon, D. Strintzi, M. Tsalas, T.W. Versloot, J. Weiland, K.-D. Zastrow, JET-EFDA collaborators

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

### Abstract

Several parametric scans have been performed to study momentum transport on JET. NBI modulation technique has been applied to separating the diffusive and convective momentum transport terms. The magnitude of the inward momentum pinch depends strongly on the inverse density gradient length, with an experimental scaling for the pinch number being $-Rv_{pinch}/\chi\phi = 1.2R/L_n + 1.4$. There is no dependence of the pinch number on collisionality. The Prandtl number was not found to depend either on R/Ln, collisionality or on q. The gyrokinetic simulations show qualitatively similar dependence of the pinch number on R/Ln, but the dependence is weaker in the simulations. Gyro-kinetic simulations do not find any clear parametric dependence in the Prandtl number, in agreement with experiments, but the experimental values are larger than the simulated ones. The extrapolation of these results to ITER illustrates that at R/Ln>2 the pinch number becomes large enough (> 3-4) to make the rotation profile peaked provided that the edge rotation is non-zero. And this rotation peaking can be achieved with small or even with no core torque source. The absolute value of the core rotation is still very challenging to predict partly due to the lack of the present knowledge of the rotation at the plasma edge, partly due to insufficient understanding of 3D effects like braking and partly due to the uncertainties in the extrapolation of the present momentum transport results to a larger device.
Original language English Proceedings 38th EPS Conference on Plasma Physics, EPS 2011 A. Becoulet European Physical Society 605-608 1 2-914771-68-1, 978-1-6183-9593-1 Published - 2011 A4 Article in a conference publication 38th European Physical Society Conference on Plasma Physics - Strasbourg, FranceDuration: 27 Jun 2011 → 1 Jul 2011

### Publication series

Name EPS 35G

### Conference

Conference 38th European Physical Society Conference on Plasma Physics EPS 2011 France Strasbourg 27/06/11 → 1/07/11

ripples
torque
momentum
modulation
magnetic fields
Prandtl number
extrapolation
braking
simulation
scaling
kinetics
profiles

### Keywords

• plasma physics

### Cite this

Tala, T., Salmi, A., Mantica, P., Angioni, C., Corrigan, G., Vries, P. C. D., ... JET-EFDA collaborators (2011). NBI Modulation Experiments to Study Momentum Transport and Magnetic Field Induced Ripple Torque on JET. In A. Becoulet (Ed.), Proceedings: 38th EPS Conference on Plasma Physics, EPS 2011 (Vol. 1, pp. 605-608). European Physical Society.
Tala, Tuomas ; Salmi, Antti ; Mantica, P. ; Angioni, C. ; Corrigan, G ; Vries, P.C. de ; Giroud, C. ; Ferreira, J. ; Lönnroth, J. ; Naulin, V. ; Peeters, A.G. ; Solomon, W. ; Strintzi, D. ; Tsalas, M. ; Versloot, T.W. ; Weiland, J. ; Zastrow, K.-D. ; JET-EFDA collaborators. / NBI Modulation Experiments to Study Momentum Transport and Magnetic Field Induced Ripple Torque on JET. Proceedings: 38th EPS Conference on Plasma Physics, EPS 2011. editor / A. Becoulet. Vol. 1 European Physical Society, 2011. pp. 605-608
title = "NBI Modulation Experiments to Study Momentum Transport and Magnetic Field Induced Ripple Torque on JET",
abstract = "Several parametric scans have been performed to study momentum transport on JET. NBI modulation technique has been applied to separating the diffusive and convective momentum transport terms. The magnitude of the inward momentum pinch depends strongly on the inverse density gradient length, with an experimental scaling for the pinch number being $-Rv_{pinch}/\chi\phi = 1.2R/L_n + 1.4$. There is no dependence of the pinch number on collisionality. The Prandtl number was not found to depend either on R/Ln, collisionality or on q. The gyrokinetic simulations show qualitatively similar dependence of the pinch number on R/Ln, but the dependence is weaker in the simulations. Gyro-kinetic simulations do not find any clear parametric dependence in the Prandtl number, in agreement with experiments, but the experimental values are larger than the simulated ones. The extrapolation of these results to ITER illustrates that at R/Ln>2 the pinch number becomes large enough (> 3-4) to make the rotation profile peaked provided that the edge rotation is non-zero. And this rotation peaking can be achieved with small or even with no core torque source. The absolute value of the core rotation is still very challenging to predict partly due to the lack of the present knowledge of the rotation at the plasma edge, partly due to insufficient understanding of 3D effects like braking and partly due to the uncertainties in the extrapolation of the present momentum transport results to a larger device.",
keywords = "plasma physics",
author = "Tuomas Tala and Antti Salmi and P. Mantica and C. Angioni and G Corrigan and Vries, {P.C. de} and C. Giroud and J. Ferreira and J. L{\"o}nnroth and V. Naulin and A.G. Peeters and W. Solomon and D. Strintzi and M. Tsalas and T.W. Versloot and J. Weiland and K.-D. Zastrow and {JET-EFDA collaborators}",
year = "2011",
language = "English",
isbn = "2-914771-68-1",
volume = "1",
publisher = "European Physical Society",
pages = "605--608",
editor = "A. Becoulet",
booktitle = "Proceedings",

}

Tala, T, Salmi, A, Mantica, P, Angioni, C, Corrigan, G, Vries, PCD, Giroud, C, Ferreira, J, Lönnroth, J, Naulin, V, Peeters, AG, Solomon, W, Strintzi, D, Tsalas, M, Versloot, TW, Weiland, J, Zastrow, K-D & JET-EFDA collaborators 2011, NBI Modulation Experiments to Study Momentum Transport and Magnetic Field Induced Ripple Torque on JET. in A Becoulet (ed.), Proceedings: 38th EPS Conference on Plasma Physics, EPS 2011. vol. 1, European Physical Society, pp. 605-608, 38th European Physical Society Conference on Plasma Physics, Strasbourg, France, 27/06/11.

NBI Modulation Experiments to Study Momentum Transport and Magnetic Field Induced Ripple Torque on JET. / Tala, Tuomas; Salmi, Antti; Mantica, P.; Angioni, C.; Corrigan, G; Vries, P.C. de; Giroud, C.; Ferreira, J.; Lönnroth, J.; Naulin, V.; Peeters, A.G.; Solomon, W.; Strintzi, D.; Tsalas, M.; Versloot, T.W.; Weiland, J.; Zastrow, K.-D.; JET-EFDA collaborators.

Proceedings: 38th EPS Conference on Plasma Physics, EPS 2011. ed. / A. Becoulet. Vol. 1 European Physical Society, 2011. p. 605-608.

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

TY - GEN

T1 - NBI Modulation Experiments to Study Momentum Transport and Magnetic Field Induced Ripple Torque on JET

AU - Tala, Tuomas

AU - Salmi, Antti

AU - Mantica, P.

AU - Angioni, C.

AU - Corrigan, G

AU - Vries, P.C. de

AU - Giroud, C.

AU - Ferreira, J.

AU - Lönnroth, J.

AU - Naulin, V.

AU - Peeters, A.G.

AU - Solomon, W.

AU - Strintzi, D.

AU - Tsalas, M.

AU - Versloot, T.W.

AU - Weiland, J.

AU - Zastrow, K.-D.

AU - JET-EFDA collaborators

PY - 2011

Y1 - 2011

N2 - Several parametric scans have been performed to study momentum transport on JET. NBI modulation technique has been applied to separating the diffusive and convective momentum transport terms. The magnitude of the inward momentum pinch depends strongly on the inverse density gradient length, with an experimental scaling for the pinch number being $-Rv_{pinch}/\chi\phi = 1.2R/L_n + 1.4$. There is no dependence of the pinch number on collisionality. The Prandtl number was not found to depend either on R/Ln, collisionality or on q. The gyrokinetic simulations show qualitatively similar dependence of the pinch number on R/Ln, but the dependence is weaker in the simulations. Gyro-kinetic simulations do not find any clear parametric dependence in the Prandtl number, in agreement with experiments, but the experimental values are larger than the simulated ones. The extrapolation of these results to ITER illustrates that at R/Ln>2 the pinch number becomes large enough (> 3-4) to make the rotation profile peaked provided that the edge rotation is non-zero. And this rotation peaking can be achieved with small or even with no core torque source. The absolute value of the core rotation is still very challenging to predict partly due to the lack of the present knowledge of the rotation at the plasma edge, partly due to insufficient understanding of 3D effects like braking and partly due to the uncertainties in the extrapolation of the present momentum transport results to a larger device.

AB - Several parametric scans have been performed to study momentum transport on JET. NBI modulation technique has been applied to separating the diffusive and convective momentum transport terms. The magnitude of the inward momentum pinch depends strongly on the inverse density gradient length, with an experimental scaling for the pinch number being $-Rv_{pinch}/\chi\phi = 1.2R/L_n + 1.4$. There is no dependence of the pinch number on collisionality. The Prandtl number was not found to depend either on R/Ln, collisionality or on q. The gyrokinetic simulations show qualitatively similar dependence of the pinch number on R/Ln, but the dependence is weaker in the simulations. Gyro-kinetic simulations do not find any clear parametric dependence in the Prandtl number, in agreement with experiments, but the experimental values are larger than the simulated ones. The extrapolation of these results to ITER illustrates that at R/Ln>2 the pinch number becomes large enough (> 3-4) to make the rotation profile peaked provided that the edge rotation is non-zero. And this rotation peaking can be achieved with small or even with no core torque source. The absolute value of the core rotation is still very challenging to predict partly due to the lack of the present knowledge of the rotation at the plasma edge, partly due to insufficient understanding of 3D effects like braking and partly due to the uncertainties in the extrapolation of the present momentum transport results to a larger device.

KW - plasma physics

M3 - Conference article in proceedings

SN - 2-914771-68-1

SN - 978-1-6183-9593-1

VL - 1

SP - 605

EP - 608

BT - Proceedings

A2 - Becoulet, A.

PB - European Physical Society

ER -

Tala T, Salmi A, Mantica P, Angioni C, Corrigan G, Vries PCD et al. NBI Modulation Experiments to Study Momentum Transport and Magnetic Field Induced Ripple Torque on JET. In Becoulet A, editor, Proceedings: 38th EPS Conference on Plasma Physics, EPS 2011. Vol. 1. European Physical Society. 2011. p. 605-608