Onset of symmetric plasma turbulence

We analyze the electrostatic turbulence in a stationary toroidal magnetopla sma, created by radio-frequency waves, and confined by a toroidal magnetic field. The increase of toroidal magnetic field, leads tol gradients, in the mean plasma radial profiles and to the enhancement of electrostatic turbul ence. Another consequence is the emergence of symmetry in the probability d istributions of fluctuations and of the time in which they return to a spec ified reference interval of values. This symmetry as well as scaling laws r eported here are typically observed in low-dimensional chaotic dynamical sy stems. Decreasing the magnetic field breaks the symmetry in the probability distribution; however, it preserves the correlation properties of a few av erage quantities. (C) 2001 Elsevier Science B.V. All rights reserved.