Central helium density measurements in PLT

Abstract

The central helium density in PLT has been deduced from measurements of the ratio of d-3He to d-d fusion reactions during deuterium neutral-beam injection. The inward transport time for 3He puffed at the edge plasma was 10 to 30 ms. The decay time of the central 3He density increased with electron density, varying from 0.3 s to greater than 1.0 s over the density range of (1–5) × 1013 cm−3