In such a case, the measured ion heat diffusion coefficients were indeed found to be at the theoretical minimum neoclassical level across the entire plasma. A sound theoretical explanation for this taming of turbulence in terms of stabilizing sheared flows in the plasma competing with turbulence growth rates is being developed. This remarkable result is an existence proof that turbulent transport can be sufficiently reduced to open the door to wide array of magnetic fusion possibilities. In this last year, experimenters have manipulated these regions of reduced transport in many ways, finding ways to enhance the sheared flows or reduce turbulence growth rates. Various different plasma heating schemes, injection of frozen deuterium pellets, and impurity injection are some of the techniques used to extend the transport barrier results from the ion transport reported in the figure to electron and particle transport.
Higher frequencies correspond to core, low to edge of plasma.
Total ion thermal diffusivity at time of peak performance. Experiments around the world have shown that the tokamak magnetic plasma confinement device has highly reproducible properties in regard to its overall stability and its rate of cross-field heat leakage. A tokamak confines plasma using a multi-million Ampere electric current flowing in the plasma. When the plasma current is produced solely by induction, its radial profile takes a simple centrally peaked shape which essentially implies conventional stability properties. Experiments have found that regimes with such current profiles are also conducive to states of reduced plasma heat leakage.