Observation of zonal flow type oscillation in linear cylindrical ECR plasmas

Zonal flow type oscillation, which is driven by a small modulation of the electron cyclotron resonance (ECR) power in a low-frequency band (< 0.1 kHz), and its impact on drift wave turbulence are observed in linear cylindrical ECR plasmas by simultaneous spatiotemporal measurements with a multi-ring probe array. It is found that a potential low-frequency (< 0.1 kHz) oscillation can have a zonal flow type structure. Bicoherence analysis reveals that this zonal flow type oscillation has a nonlinear interaction with the drift mode. These results indicate that an electric field with zonal flow, which is excited externally, can modulate the drift mode amplitude, similar to spontaneous zonal flow.