Ion‐temperature‐gradient instability driven transport and its parametric scaling

Abstract

Experiments are reported on the ion thermal transport due to the ion‐temperature‐ gradient‐driven instability (ITG mode) and its transport scaling properties with respect to instability parameters like fluctuation level n/ni and linear growth rate as well as the drive parameter ηi(=∂ ln[Ti]/∂ ln[ni]) in the Columbia Linear Machine [Phys. Fluids 26, 1044 (1983)]. The measured local ion thermal conductivity χ⊥(r) is highly anomalous and strongly correlated with the radial profile of the ITG mode. The linear scaling of the averaged thermal conductivity 〈χ⊥(r)〉 with the averaged mode fluctuation level 〈n/ni〉 and linear growth rate indicates strong turbulence‐type scaling. The scaling of χ⊥ with the drive parameter ηi is offset linear.