|Title||Ion heat transport studies in JET|
|Publication Type||Journal Article|
|Year of Publication||2011|
|Authors||P. Mantica, C. Angioni, B. Baiocchi, M. Baruzzo, M.NA Beurskens, J.PS Bizarro, R.V Budny, P. Buratti, A. Casati, C. Challis, J. Citrin, G. Colyer, F. Crisanti, A.CA Figueiredo, L. Frassinetti, C. Giroud, N. Hawkes, J. Hobirk, E. Joffrin, T. Johnson, E. Lerche, P. Migliano, V. Naulin, A.G. Peeters, G. Rewoldt, F. Ryter, A. Salmi, R. Sartori, C. Sozzi, G. Staebler, D. Strintzi, T. Tala, M. Tsalas, D. Van Eester, T. Versloot, P.C de Vries, J. Weiland|
|Journal||Plasma Physics and Controlled Fusion|
|Type of Article||Article|
|Keywords||ASDEX UPGRADE, CONFINEMENT, H-MODE PLASMAS, INSTABILITIES, RATIO, SHEAR, T-E/T-I, THERMAL TRANSPORT, TOKAMAKS, TURBULENCE SIMULATIONS|
Detailed experimental studies of ion heat transport have been carried out in JET exploiting the upgrade of active charge exchange spectroscopy and the availability of multi-frequency ion cyclotron resonance heating with (3)He minority. The determination of ion temperature gradient (ITG) threshold and ion stiffness offers unique opportunities for validation of the well-established theory of ITG driven modes. Ion stiffness is observed to decrease strongly in the presence of toroidal rotation when the magnetic shear is sufficiently low. This effect is dominant with respect to the well-known omega(ExB) threshold up-shift and plays a major role in enhancing core confinement in hybrid regimes and ion internal transport barriers. The effects of T(e)/T(i) and s/q on ion threshold are found rather weak in the domain explored. Quasi-linear fluid/gyro-fluid and linear/non-linear gyro-kinetic simulations have been carried out. Whilst threshold predictions show good match with experimental observations, some significant discrepancies are found on the stiffness behaviour.
|Alternate Title||Plasma Phys. Control. Fusion|
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