Plasma density and poloidal field measurements on TEXT using an injected lithium beam (invited)

Spectroscopy of an injected Li beam has been used to determine both the plasma density profile and the poloidal field profile on the TEXT tokamak. The neutral Li beam is injected at energies up to 95 keV and both collisional and laser‐induced fluorescence are observed during a tokamak shot. Radial and temporal profiles are obtained during a complete shot. The applicability of this technique to larger tokamaks depends on several parameters including (but not limited to) beam penetration, reliability, spatial/temporal resolution, and signal‐to‐noise ratio. Because this basic technique obtains local measurements, it is also applicable to nonsymmetric devices. Such applications will be discussed.