Strong Nonlocal Effects in a Tokamak Perturbative Transport Experiment

Abstract

A finite but small injection of carbon into the TEXT tokamak edge induces significant temperature perturbations throughout the plasma. Large, rapid temperature decreases are observed in the outer third, while temperatures in the inner third promptly begin to rise. The effects cannot be reproduced with transport coefficients that are functions only of local thermodynamic variables. A large increase in ${\ensuremath{\chi}}_{e}$ must occur within 100 \ensuremath{\mu}s in the outer region, and ${\ensuremath{\chi}}_{e}$ must simultaneously begin to decrease in the interior. Increases in local density fluctuation levels coincide with the increase in ${\ensuremath{\chi}}_{e}$.