Experimental Study of Isotope Scaling of Ion Thermal Transport

The wide divergence between most theoretical predictions of isotopic mass scaling of transport and tokamak experimental results motivated a basic physics experiment in the Columbia Linear Machine [R. Scarmozzino, A. K. Sen, and G. A. Navratil, Phys. Rev. Lett. 57, 1729 (1986)]]. The experiments on ion thermal conductivity due to ion temperature gradient-driven slab modes are performed using two different gases: hydrogen and deuterium. The results indicate inverse dependence of ion thermal conductivity on the isotope mass close to K(radially) approximately A(-0.5)(i). This is similar to the tokamak results, but in stark contradiction to most present theoretical models.