MEASUREMENT OF NEUTRAL DENSITY PROFILE IN TEXT USING A DIAGNOSTIC NEUTRAL BEAM

We use a diagnostic neutral beam, a scanning neutral particle energy analyzer, and Hα measurements to estimate the neutral density profile from the edge to the center of the TEXT tokamak. The diagnostic neutral beam provides a spatially localized density of neutrals. The plasma neutral density is measured from the ratio of the signals seen with and without the beam. The Hα measurements provide neutral profiles in the edge region and the global particle confinement time τp. The shapes of the observed neutral energy spectra put a lower bound on the central neutral density. Results are compared with estimates of NUT and general agreement is found. Error estimates are given.