NBI modulation experiments to study momentum transport and magnetic field induced ripple torque on JET
Paper in proceedings, 2011

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 pmch/ X φ= 1.2RJL n + 1.4. There is no dependence of the pinch number on collisionality. The Prandtl number was not found to depend either on R/L n, collisionality or on q. The gyro- kinetic simulations show qualitatively similar dependence of the pinch number on R/L n, 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/L n>2 the pinch number becomes large enough (> 3-4) to make the rotation profile peaked provided that the edge rotation is non-zero. 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.

Collisionality

Momentum transports

Parametric dependence

Modulation techniques

Plasma edges

Absolute values

Kinetic simulation

Experimental values

Inverse density

Ripple torque

Core rotation

3D effects

Author

T. Tala

Technical Research Centre of Finland (VTT)

A. Salmi

Aalto University

P. Mantica

Consiglo Nazionale Delle Richerche

C. Angioni

Max Planck Society

G. Corrigan

EURATOM/CCFE Fusion Association

P.C. de Vries

Foundation for Fundamental Research on Matter

C. Giroud

EURATOM/CCFE Fusion Association

J. Ferreira

Instituto Superior Tecnico

J. Lönnroth

Aalto University

V. Naulin

Technical University of Denmark (DTU)

A.G. Peeters

University of Bayreuth

W. Solomon

Princeton University

D. Strintzi

National Technical University of Athens (NTUA)

M. Tsalas

Foundation for Fundamental Research on Matter

T.W. Versloot

Foundation for Fundamental Research on Matter

Jan Weiland

Chalmers, Earth and Space Sciences, Transport Theory

K.-D. Zastrow

EURATOM/CCFE Fusion Association

38th EPS Conference on Plasma Physics 2011, EPS 2011. Strasbourg, 27 June - 1 July 2011

Vol. 35 1 605-608

Subject Categories

Physical Sciences

ISBN

978-161839593-1

More information

Latest update

11/5/2020