Measurements of the local ion temperature gradient in the PLT tokamak and its use in the analysis of the ion energy balance

Local ion temperature gradients were measured at two radial positions in the PLT tokamak by counting the escaping d(d,p)t protons on orbits at closely spaced intervals. A single surface barrier detector was used to make each gradient measurement, eliminating relative calibration uncertainties. The ion thermal diffusivities inferred through ion energy balance with the measured temperature gradients are within a factor of two of the Chang-Hinton neoclassical values for the 3He minority ICRH plasmas.