Confinement improvement in beam heated ISX-B discharges with low-z impurity injection

Abstract Results are reported on improved confinement in the Impurity Study Experiment (ISX-B) neutral beam heated plasmas when a small amount of neon is injected shortly after the start of beam heating. The scaling of energy confinement is modified by the introduction of a dependence on line-averaged density. Calculations show the improvement is primarily caused by a reduction in electron heat conduction.