Impurity transport, turbulence transitions and intrinsic rotation in Alcator C-Mod plasmas
Name
Anne White Howard - Plasma Phys Control Fus 56 12 2014 - 13ja062_full.pdf
Size
983.91 KB
Format
Adobe PDF
Checksum (MD5)
4bca77234d59a83b5563a290b4f9b5a8
Author(s)
Holland, C.
Howard, N. T.
White, Anne E.
Greenwald, Martin J
Rice, John E
Date Issued
November 2014
Journal
Plasma Physics and Controlled Fusion
Publisher
IOP Publishing
Citation
Howard, N T et al. “Impurity Transport, Turbulence Transitions and Intrinsic Rotation in Alcator C-Mod Plasmas.” Plasma Physics and Controlled Fusion 56.12 (2014): 124004.
Version
Author's final manuscript
Abstract
Linear and nonlinear gyrokinetic simulations are used to probe turbulent impurity transport in intrinsically rotating tokamak plasmas. For this simulation-based study, experimental input parameters are taken from a pair of ICRF heated Alcator C-Mod discharges exhibiting a change in the sign of the normalized toroidal rotation gradient at mid-radius (i.e. a change from hollow to peaked intrinsic rotation profiles). The simulations show that there is no change in the peaking of the calcium impurity between the plasmas with peaked and hollow rotation profiles, suggesting that the impurity transport and the shape of the rotation do not always change together. Furthermore, near mid-radius, r/a = 0.5 (normalized midplane minor radius), the linear and nonlinear gyrokinetic simulations exhibit no evidence of a transition from ion temperature gradient (ITG) to trapped electron mode dominance when the intrinsic rotation profile changes from peaked to hollow. Extensive nonlinear sensitivity analysis is performed, and there is no change in the ITG critical gradient or in the stiffness of ion heat transport with the change in the intrinsic toroidal rotation profile shape, which suggests that the shape of the rotation profile is not dominated by the ITG onset in these cases.
MIT Department
Massachusetts Institute of Technology. Plasma Science and Fusion Center
Terms of Use
Creative Commons Attribution-Noncommercial-Share Alike
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1088/0741-3335/56/12/124004
