Radial density profiles of highly charged carbon ions in TEXTOR

Abstract First results of the application of lithium-beam activated charge exchange spectroscopy (Li-CXS) to a tokamak edge plasma are reported. Radial density profiles of several highly ionized states of carbon (C 4+ to C 6+ ) have been measured in the outmost 20 cm of ohmically heated TEXTOR discharges. Based on these profiles, the transport of carbon being released from limiter surfaces has been studied by applying a one-dimensional steady-state particle balance equation, which contains convective and diffusive parts. To explain the experimentally measured profiles within the model used, an additional outward convection velocity has to be assumed.