TY  - JOUR
AU  - Tokar, M. Z.
TI  - Mechanism of central temperature peaking in impurity seeded plasmas
JO  - Plasma physics and controlled fusion
VL  - 45
SN  - 0741-3335
CY  - Bristol
PB  - IOP Publ.
M1  - PreJuSER-28008
SP  - 1323 - 1332
PY  - 2003
N1  - Record converted from VDB: 12.11.2012
AB  - Formation of a centrally peaked profile of the ion temperature by impurity seeding has been observed in all the largest tokamaks: JET, JT-60U, TFTR. A possible explanation of this phenomenon is proposed, which takes into account the suppression of ion temperature gradient instability induced anomalous transport through increasing ion effective charge Z(eff) and Doppler shift of unstable modes, S-perpendicular to. The particular importance of the S-perpendicular to component proportional to the temperature gradient, which stems from the pressure gradient and neoclassical poloidal rotation, is elucidated. It is demonstrated that this contribution grows significantly by impurity seeding when the rotation regime changes due to increased collisionality. An interrelation between the heating power density and Z(eff) necessary for the transition to a peaked ion temperature is found. The modification of radial profiles by impurity seeding is modelled numerically and the results are in agreement with the experimental data from JET.
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000184656800021
DO  - DOI:10.1088/0741-3335/45/7/319
UR  - https://juser.fz-juelich.de/record/28008
ER  -