Key to Improved Ion Core Confinement in the JET Tokamak: Ion Stiffness Mitigation due to Combined Plasma Rotation and Low Magnetic Shear
2010 (English)Conference paper (Other academic)
New experimental evidence indicates that ion stiffness mitigation in the core of rotating plasmas, observed previously in JET, results from the combined effect of high rotational shear and low magnetic shear. Ionstiffness in the outer plasma region is found to remain very high irrespective of rotation. Dedicated experimentsin plasmas with different q profiles and rotation levels point to a larger effect of rotation in reducing stiffnesswhen the core q profile is made flatter. The results have implications for the understanding of improved ion coreconfinement in hybrid plasmas or Internal Transport Barriers, both characterized by high rotation and low magnetic shear. Experimental evidence in these scenarios is discussed. Simulations indicate that the physics behindthese results may lie in the ITG/TEM turbulence behavior at the transition between fully developed turbulenceand zonal flows quenching. These findings point to the need for future devices of achieving sufficient rotationalshear and capability of q profile manipulation to reach improved ion core confinement, which is an essentialfeature of Advanced Tokamak operation.
Place, publisher, year, edition, pages
IAEA , 2010.
Fusion, Plasma and Space Physics
IdentifiersURN: urn:nbn:se:kth:diva-55837OAI: oai:DiVA.org:kth-55837DiVA: diva2:471847
23rd IAEA Fusion Energy Conference, 11-16 October 2010
QC 201204102012-01-032012-01-032012-04-10Bibliographically approved