TY - JOUR
T1 - Plasma rotation and momentum transport studies at JET
AU - de Vries, P.C.
AU - Rantamäki, K.M.
AU - Giroud, C.
AU - Asp, E.
AU - Corrigan, G.
AU - Eriksson, A.
AU - de Greef, M.
AU - Jenkins, I.
AU - Knoops, H.C.M.
AU - Mantica, P.
AU - Nordman, H.
AU - Strand, P.
AU - Tala, T.
AU - Weiland, J.
AU - Zastrow, K.D.
PY - 2006/12/1
Y1 - 2006/12/1
N2 - An experimental study in plasma rotation and momentum transport was carried out at JET. The toroidal rotation profile was found to scale approximately with that of the ion temperature. However, significant deviations from this were found in high density ELMy H-mode discharges, which had broader rotation profiles. A rotation database analysis showed the variation of the dimensionless Mach number with respect to the plasma scenario. For predominantly NBI heated discharges the Mach number was found to be in the range of 0.3-0.45. Larger Mach numbers were observed in type I ELMy H-modes, while scenarios exhibiting type III ELMs or L-mode had lower Mach numbers. Advanced scenarios often showed a significant increase in the central Mach number when an internal transport barrier formed. A detailed study was done to investigate the Prandtl number, Pr, defined as the ratio between momentum and ion heat diffusivity. Generally the Prandtl number was found to be significantly below unity, e.g. 0.18 < Pr < 0.35. Although it is often predicted that momentum and heat diffusivity are equal in ITG dominated plasma, also for high density ELMy H-mode discharges with temperature profiles close and above the ITG threshold, the Prandtl number was Pr ∼ 0.3.
AB - An experimental study in plasma rotation and momentum transport was carried out at JET. The toroidal rotation profile was found to scale approximately with that of the ion temperature. However, significant deviations from this were found in high density ELMy H-mode discharges, which had broader rotation profiles. A rotation database analysis showed the variation of the dimensionless Mach number with respect to the plasma scenario. For predominantly NBI heated discharges the Mach number was found to be in the range of 0.3-0.45. Larger Mach numbers were observed in type I ELMy H-modes, while scenarios exhibiting type III ELMs or L-mode had lower Mach numbers. Advanced scenarios often showed a significant increase in the central Mach number when an internal transport barrier formed. A detailed study was done to investigate the Prandtl number, Pr, defined as the ratio between momentum and ion heat diffusivity. Generally the Prandtl number was found to be significantly below unity, e.g. 0.18 < Pr < 0.35. Although it is often predicted that momentum and heat diffusivity are equal in ITG dominated plasma, also for high density ELMy H-mode discharges with temperature profiles close and above the ITG threshold, the Prandtl number was Pr ∼ 0.3.
UR - http://www.scopus.com/inward/record.url?scp=33846074857&partnerID=8YFLogxK
U2 - 10.1088/0741-3335/48/12/001
DO - 10.1088/0741-3335/48/12/001
M3 - Article
AN - SCOPUS:33846074857
VL - 48
SP - 1693
EP - 1708
JO - Plasma Physics and Controlled Fusion
JF - Plasma Physics and Controlled Fusion
SN - 0741-3335
IS - 12
M1 - 001
ER -