Theory-based transport modelling of tokamak temperature and density profiles

Conference · Tue Dec 31 04:00:00 EST 1996

OSTI ID:489418

Bateman, G; Kinsey, J E; Kritz, A H; Redd, A J ^[1]

---

1. Lehigh Univ., Bethlehem, PA (United States); and others

We use a combination of theoretically derived transport models in transport simulation codes to predict the temperature and density profiles in tokamaks. The simulated profiles match experimental data well for more than 50 discharges from at least 7 different tokamaks including L-mode scans in current, heating power, density, normalized gyro-radius ({rho}*), collisionality ({nu}*) and {beta}, as well as TFTR supershot current scans and a variety of discharges from the ITER Profile Database. The transport model in these simulations combines the Weiland Ion Temperature Gradient and Trapped Electron Mode model together with the Guzdar-Drake resistive ballooning mode model as well as smaller contributions from kinetic ballooning modes and neoclassical transport. For resistive ballooning modes, we found that the nominal Guzdar-Drake model matches current scan data better than the nominal Carreras-Diamond model (i.e., with coefficient 1.0). The simulations of the {rho} scans from DIII-D, TFTR and JET are particularly interesting because we find that our fundamentally gyro-Bohm transport models produce the observed non gyro-Bohm behavior of the experimental data. Since edge neutrals penetrate less far into into the higher density (lower {rho}*) plasmas, they change the shape of the density and collisionality profiles near the plasma edge which, in turn, changes the scaling of the transport. This effect cascades into the core of the plasma, where small changes in profile shape have a relatively large effect on the transport. Supershot simulations are also strongly affected by the influx of edge neutrals. Our predictive simulations of experimentally measured data using theoretically derived transport models have lead to some surprising new insights.

• DOE Contract Number: FG02-92ER54141
• OSTI ID: 489418
• Report Number(s): CONF-960354--
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BALLOONING INSTABILITY
CHARGED-PARTICLE TRANSPORT THEORY
PLASMA DENSITY
PLASMA SIMULATION
TEMPERATURE DISTRIBUTION
TOKAMAK DEVICES