A first assessment of low-Z impurity transport in beam-heated NSTX H-modes has been performed using magnetic field and current scans at fixed q-profile as well as temperature scans at constant plasma density, current and toroidal field. Impurity diffusivity levels consistent with the neoclassical predictions have been found, whereas a reversal of the convective velocity at low fields indicates an anomalous effect to be at play at the gradient region. Studies on the impact of rotation in low-density H-modes have also shown that heavy and not fully stripped impurities with high Mach numbers can experience core diffusivities several times larger than that of the 'standard' neoclassical transport for stationary plasmas, without the need of invoking the presence of long wavelength core electrostatic turbulence. As a result of a deliberate neon impurity injection we have also observed a correlation between the strength of the emitted radiation, the earlier appearance of tearing modes activity and an enhanced plasma cooling that resulted in enlarged magnetic islands.
Charge dependence of neoclassical and turbulent transport of light impurities on MAST