Ubiquity of non-diffusive momentum transport in JET H-modes

A broad survey of the experimental database of neutral beam heated baseline H-modes and hybrid scenarios in the JET tokamak has established the ubiquity of non-diffusive momentum transport mechanisms in rotating plasmas. As a result of their presence, the normalized angular frequency gradient R del omega/omega is higher than expected from momentum diffusion alone, by about unity in the core (r/a similar to 0.3), rising to near 5 close to the edge, where its contribution to the total gradient is comparable to the gradient associated with the diffusive flux. The magnitude and parameter dependences of the non-diffusive contribution to the gradient are consistent with a theoretically expected pinch, which has its origin in the vertical particle drift resulting from the Coriolis force. Linear gyrokinetic calculations of the pinch number RV/chi(phi) and the Prandtl number chi(phi)/chi(i) are in good agreement with the experimental observations, with similar dependences on R/L-n, q and epsilon = r/R. A contribution due to residual stresses may also be present, but could not be identified with certainty.


Published in:
Nuclear Fusion, 52, 11
Presented at:
13th International Workshop on H-Mode Physics and Transport Barriers, Oxford, England, October 2011
Year:
2012
Publisher:
Vienna, Int Atomic Energy Agency
ISSN:
0029-5515
Laboratories:
SPC
CRPP




 Record created 2013-02-27, last modified 2018-09-13


Rate this document:

Rate this document:
1
2
3
 
(Not yet reviewed)