Edge transport measurements with the new multi-energy soft-x-ray diagnostic on NSTX

NSTX is a large spherical torus designed to study plasma confinement and stability at low aspect ratios. Recent research on the device has focused on the plasma edge, as particle transport in this region has a large impact on global confinement. The effects of lithium-coated PFCs and 3D magnetic field perturbations on edge transport are of particular interest. With steep gradients in the edge, radial transport measurements require diagnostics with spatial resolution on the order of the ion gyroradius (∼ 1 cm). Sub-millisecond time resolution is required for perturbative transport techniques and to study transients such as ELMs. Measuring transport with this high resolution in the sub-keV plasma edge is quite challenging.