Combined operation of pellet injection and lower hybrid current drive in ASDEX

Simultaneous operation of lower hybrid current drive and pellet injection could be successfully achieved. With peripheral ablation of the pellets by suprathermal electrons, the same net inward flux of particles is found as with deep penetration of pellets into Ohmically heated plasmas. The density profile n e (r) peaks with the same increment of the peaking factor Q n =n e0 /(n e ) in both cases. The global energy confinement time rises with density, tau E approximately n e , in the combined operation.