Gyrofluid simulations of turbulence suppression in reversed-shear experiments on the Tokamak Fusion Test Reactor
Citations Over TimeTop 1% of 1997 papers
Abstract
The confinement improvement in reversed-shear experiments on the Tokamak Fusion Test Reactor [Plasma Phys. Controlled Fusion 26, 11 (1984)] is investigated using nonlinear gyrofluid simulations including a bounce-averaged trapped electron fluid model. This model includes important kinetic effects for both ions and electrons, and agrees well with linear kinetic theory. Both reversed shear and the Shafranov shift reverse the precession drifts of a large fraction of the trapped electrons, which significantly reduces the growth rate of the trapped electron mode, found to be the dominant instability in the core. Two positive feedback transition mechanisms for the sudden improvement in core confinement are discussed: (1) Shafranov shift suppression of the trapped electron mode, and (2) turbulence suppression by radially sheared E×B flows. While both effects appear to be playing roles in the transition dynamics in most experiments, we show that Shafranov shift stabilization alone can cause a transition.
Related Papers
- → Mode–particle resonances during near-tangential neutral beam injection in the Tokamak Fusion Test Reactor(1990)27 cited
- → Large Tokamak Experiments (Report on the 2nd IAEA Technical Committee Meeting, Princeton, 1976)(1977)23 cited
- Computational studies of impurity effects, impurity control, and neutral-beam injection in large tokamaks(1978)
- → First plasma at Princeton's Tokamak Fusion Test Reactor(1983)
- → Investigation of a coherent instability with an ion beam probe(1974)