Sensitivity Study of Predictions of an ITG-based Transport Model

G.W. Hammett, M.A. Beer, W. Dorland*, M. Kotschenreuther#
Princeton Plasma Physics Lab
* University of Maryland, Inst. for Plasma Research
# University of Texas, Inst. for Fusion Studies

Poster Q7S37, as presented at the Fortieth Annual Meeting of the American Physical Society Division of Plasma Physics, New Orleans, November 16-20, 1998. Abstract in Bull. American Phys. Soc. 43, 1877 (1998).

We investigate the effects of various assumptions in an ITG-based transport model on the predicted fusion power performance of various tokamak reactor designs. Among other sources of variability, the effect of modifying the IFS-PPPL model (originally based on gyrofluid simulations) to roughly fit the lower turbulence levels of gyrokinetic simulations is shown. There is a strong dependence on the assumed H-mode pedestal temperature. Various models for the scaling of the pedestal temperature are considered\footnote{M. Kotschenreuther, W. Dorland,, Proc. 16th Int. Conf. Plasma Physics and Control. Nucl. Fusion Res. (IAEA 1996); F.W. Perkins ibid; T. Hatae, Plasma Phys. Control. Fusion {\bf 40} 1073 (1998).}, but they all share some common features that suggest that performance might be improved significantly for compact, higher field tokamak designs with stronger plasma shaping\footnote{Y. Kamada Plasma Phys. Control. Fusion {\bf 38}, 1387 (1996).} and density peaking, such as in ARIES-RS or similar designs. However, more work is needed to be confident of these scalings. This work supported by DoE Contract DE-AC02-76CH03073, the Numerical Tokamak Turbulence Project, and NERSC computing resources.

full poster (pdf format)