Using the TCABR tokamak facility, we analyze turbulent electrostatic fluctuations in a stationary toroidal magnetoplasma, created by radio-frequency waves and confined by two different toroidal magnetic fields. The increase of toroidal magnetic field leads to gradients in the mean plasma radial profiles and the onset of electrostatic turbulence. For the turbulent fluctuations, we show that the statistics of data collected using fixed sampling time is the same than the statistics of the time in which measurements of the data return to a specified reference interval of values. With these statistical analyses we find special invariant probability distributions, power-scaling laws for some average quantities, and long-range correlation for their oscillations. These observations suggest that turbulence has recurrent properties, as those observed in recurrent fully chaotic low-dimensional systems. Therefore, evolution of measurements of low-dimensional dynamical systems can be used to describe the recurrence observed in the tokamak edge turbulence.
- drift waves
- toroidal plasma