Identification of Low-Frequency Zonal Flow in a Linear Magnetic Plasma Device

A low-frequency (f<2 kHz) potential structure (LFPS) is observed in a linear magnetic plasma device using Langmuir probe arrays. The center frequency of this structure is near zero. This structure has azimuthal and axial symmetries while with a finite radial wavenumber. The complete 3D spectra features of this structure have been identified to have the characteristics expected for zonal flows.