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

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 ñ/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 〈ñ/ni〉 and linear growth rate indicates strong turbulence-type scaling. The scaling of χ⊥ with the drive parameter ηi is offset linear.