Measurements of edge density profiles on TdeV using the injection of laser-ablated lithium atoms

Abstract

An atom injector using laser blow off of lithium is installed on TdeV to obtain the radial edge profile of electron density near the throat of the top divertor. The profile is reconstructed from the emissivity of the LiI (2p 2P→2s 2S) transition at 670.8 nm. A short review of the diagnostic is given describing the experimental setup, the measurement procedures, and the density profile reconstruction method. Effects of plasma biasing on the edge electron density profile and the response of the edge profile to the line-average central electron density are shown to illustrate the diagnostic capabilities.