Observation of intermittent structures associated with the low-frequency turbulence in toroidal magnetized plasma

Two-dimensional structures in a plane perpendicular to the magnetic field, of the low-frequency turbulence in a toroidal plasma, have been studied. The probability distribution functions for the density and the potential fluctuations are found to deviate from the Gaussian distribution significantly indicating intermittency in the turbulence and formation and destruction of the coherent structures in the strongly turbulent state. The presence of such short-lived structures has been established, on a statistical basis, by means of conditional averaging of the fluctuation amplitudes.