A basic experiment on isotope scaling of transport

There is considerable divergence between theoretical predictions and tokamak experimental results for the isotopic mass effects on transport. This motivated a basic physics experiment in the Columbia Linear Machine [G. A. Navratil, J. Slough, and A. K. Sen, Phys. Plasmas 24, 184 (1982)]. Experiments were done using two different gases: hydrogen and deuterium. Measurements of particle transport driven by an E x B rotationally driven mode were made via the cross correlation of potential and density fluctuations. Unlike in tokamaks, the plasma parameter profiles and fluctuation spectra were maintained nearly invariant for both gases, thus enabling a meaningful comparison and estimation of scaling. The first series of data reveal smaller transport values for the deuterium plasma and a scaling that ranges as D#perpendicular∝#Ai-0.6 to D#perpendicular∝#Ai-0.8