Statistics of plasma fluctuations in runaway discharges in TCABR tokamak

Abstract

In this work we analyze the spikes in the Ha emission, and density turbulence in runaway discharges in the TCABR tokamak. For the plasma edge density fluctuations, we find a symmetric-recurrent-type turbulence, with the same statistics found in measures of low-dimensional recurrent chaotic systems. For the plasma core fluctuations, we note that the line density oscillations are synchronized to the Ha oscillations. In addition, we suggest that both the onset of the Ha spikes and the line density oscillations are triggered by a process similar to the bifurcation responsible for the firing of neurons.