Experimental evidence of ambient turbulence preceding the thermal quench of disruptive plasmas.

Abstract

Plasma disruption in tokamaks is one of the most serious challenges in fusion research. Recent studies suggest that microturbulence may play an important role in facilitating thermal quench (TQ) and resultant disruptions, but experimental evidence on the impact of turbulence on the dynamic evolution of TQ is lacking. In this paper, we present a comprehensive observation using high spatiotemporal resolution, two-dimensional images of electron temperature fluctuations, which shows that before TQ for the initial heat transfer passing through the island X point, turbulence magnitudes, correlation lengths, and propagation characteristics are all significantly enhanced, revealing crucial effects of turbulence on propelling energy quench. Our findings provide direct evidence that ambient turbulence may play a role in facilitating TQ and subsequent disruption in tokamak plasmas.