Scrape-off layer turbulence modulated by Mirnov oscillations

Abstract

We investigate plasma turbulence at the scrape-off layer of TCABR tokamak. We apply a power spectral analysis to the magnetic Mirnov oscillations and electrostatic fluctuations, to quantify statistical properties and to estimate the turbulence-driven radial-particle flux. A distinctive peculiarity is the modulation of electrostatic turbulence by the Mirnov oscillations shown by the partial superposition of the frequency power spectra of these two oscillations. This characteristic allows us to investigate any possible influence of the Mirnov oscillations on particle transport. In fact, a significant part of this transport occurs at the Mirnov frequencies. The effect of this modulation is also analyzed for discharges modified by external perturbations, a DC biased electrode or an ergodic magnetic limiter.