Ohmic energy confinement saturation and core toroidal rotation reversal in Alcator C-Mod plasmas

Ohmic energy confinement saturation is found to be closely related to core toroidal rotation reversals in Alcator C-Mod tokamak plasmas. Rotation reversals occur at a critical density, depending on the plasma current and toroidal magnetic field, which coincides with the density separating the linear Ohmic confinement regime from the saturated Ohmic confinement regime. The rotation is directed co-current at low density and abruptly changes direction to counter-current when the energy confinement saturates as the density is increased. Since there is a bifurcation in the direction of the rotation at this critical density, toroidal rotation reversal is a very sensitive indicator in the determination of the regime change. The reversal and confinement saturation results can be unified, since these processes occur in a particular range of the collisionality. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3695213]


Published in:
Physics Of Plasmas, 19, 5, 056106
Year:
2012
Keywords:
Laboratories:
SPC
CRPP




 Record created 2012-08-03, last modified 2018-01-28


Rate this document:

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