Maximum Energy-Confinement Time in Joule-Heated Tokamaks

Abstract

Measurements of the energy confinement time ${\tau }_E$ in the ISX-$A$ (Impurity Study Experiment) tokamak are interpreted theoretically using a one-dimensional time-dependent transport code. The maximum ${\tau }_E$ observed as the plasma density is varied over a wide range occurs at that density above which anomalous electron thermal conductivity leads to a smaller energy flux than neoclassical ion thermal conductivity.