Trapped gyro-Landau-fluid transport modeling of DIII-D hybrid discharges
- General Atomics, P.O. Box 85608, San Diego, California 92186 (United States)
Previous work has summarized the physics and first results of benchmarking the trapped gyro-Landau-fluid (TGLF) model for turbulent transport driven by trapped ion and electron modes, ion and electron temperature gradient (ETG) modes, and electromagnetic kinetic ballooning modes including the effects of shaped geometry. Recently, an improved collision model was implemented which provides a more accurate fit to a transport database of nonlinear collisional GYRO[J. Candy and R. E. Waltz, J. Comput. Phys. 186, 545 (2003)] simulations of long wavelength driftwave turbulence. The impact of the new collision model on TGLF modeling results was unknown. Using the improved TGLF model we obtain excellent agreement with the ion and electron temperature profiles from 30 DIII-D [A. Mahdavi and J. L. Luxon, Fusion Sci. Technol. 48, 2 (2005)] hybrid discharges. The transport results show that the electron energy transport tends to be dominated by short wavelength ETG modes in cases where the ion energy transport approaches neoclassical levels. The hybrid regime has significant energy confinement improvement from ExB velocity shear which is well predicted by TGLF. Weak magnetic shear and low safety factor are also shown to enhance the hybrid regime energy confinement. In high normalized {beta} hybrids, we find that finite {beta} effects noticably reduce the predicted electron energy transport and improve agreement with the measured electron temperature profiles.
- OSTI ID:
- 21532083
- Journal Information:
- Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 12 Vol. 17; ISSN PHPAEN; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BALLOONING INSTABILITY
CHARGED-PARTICLE TRANSPORT
CLOSED PLASMA DEVICES
CONFINEMENT
DOUBLET-3 DEVICE
ELECTRIC DISCHARGES
ELECTRON TEMPERATURE
INSTABILITY
ION TEMPERATURE
NONLINEAR PROBLEMS
PLASMA CONFINEMENT
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
PLASMA SIMULATION
RADIATION TRANSPORT
SIMULATION
TEMPERATURE GRADIENTS
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
TURBULENCE