Time evolution of power spectrum density in spontaneous transition in cylindrical magnetized plasma

Preliminary observation results are reported for a new discharge regime in the Plasma Assembly for Nonlinear Turbulent Analysis (PANTA), where spontaneous transitions in the equilibrium profile and fluctuation spectra occur. Two different states are defined by using the mean density value. Axial and radial profiles are observed for the two states, and large profile changes are found. The spatiotemporal evolution of the transition front is measured. Changes in the fluctuation spectrum are evaluated using conditional average and lock-in average. (author)