Improved High-Confinement Mode with Neon Injection in the DIII-D Tokamak

The first observation of a high-confinement mode with reduced energy transport in both the center and the edge induced by the injection of neon impurities is reported in this paper. This improved high mode develops from an improved low-confinement mode. Linear growth rate calculations indicate that a new theoretical mechanism, the stabilization of high wave number drift waves by impurities, is at work, combined with $\mathbf{E}\times \mathbf{B}$ velocity shear suppression of low wave number instabilities.