Effect of toroidal field ripple on plasma rotation in JET

Journal Article · Tue Jan 01 00:00:00 EST 2008 · Nuclear Fusion

DOI:https://doi.org/10.1088/0029-5515/48/3/035007· OSTI ID:1000312

De Vries, P ^[1]; Salmi, A ^[2]; Parail, V ^[3]; Giroud, C ^[3]; Andrew, Y ^[3]; Biewer, Theodore M ^[4]; Crombe, K ^[5]; Jenkins, I ^[3]; Johnson, T ^[6]; Kiptily, V ^[3]; Loarte, A ^[7]; Lonnroth, J ^[8]; Meigs, A G ^[3]; Oyama, N ^[9]; Sartori, R ^[10]; Sabene, G ^[10]; Urano, H ^[9]; Zastrow, K-D ^[3]

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1. Culham Centre for Fusion Energy, Culham, UK
2. Helsinki University of Technology, Helsinki, Finland
3. EURATOM / UKAEA, UK
4. ORNL
5. Ghent University, Belgium
6. Association EURATOM-KTH, Sweden
7. ITER Organization, Cadarache, France
8. Association Euratom-Tekes, Finland
9. Japan Atomic Energy Agency (JAEA)
10. EFDA, Garching, Germany

Dedicated experiments on TF ripple effects on the performance of tokamak plasmas have been carried out at JET. The TF ripple was found to have a profound effect on the plasma rotation. The central Mach number, M, defined as the ratio of the rotation velocity and the thermal velocity, was found to drop as a function of TF ripple amplitude ( ) from an average value of M = 0.40 0.55 for operations at the standard JET ripple of = 0.08% to M = 0.25 0.40 for = 0.5% and M = 0.1 0.3 for = 1%. TF ripple effects should be considered when estimating the plasma rotation in ITER. With standard co-current injection of neutral beam injection (NBI), plasmas were found to rotate in the co-current direction. However, for higher TF ripple amplitudes ( ~ 1%) an area of counter rotation developed at the edge of the plasma, while the core kept its co-rotation. The edge counter rotation was found to depend, besides on the TF ripple amplitude, on the edge temperature. The observed reduction of toroidal plasma rotation with increasing TF ripple could partly be explained by TF ripple induced losses of energetic ions, injected by NBI. However, the calculated torque due to these losses was insufficient to explain the observed counter rotation and its scaling with edge parameters. It is suggested that additional TF ripple induced losses of thermal ions contribute to this effect.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1000312
• Journal Information: Nuclear Fusion, Vol. 48, Issue 3; ISSN 0029-5515
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
AMPLITUDES
BEAM INJECTION
MACH NUMBER
PERFORMANCE
PLASMA
ROTATION
TAIL IONS
TORQUE
VELOCITY
plasma h-mode