A probe array for the investigation of spatio‐temporal structures in drift wave turbulence

A probe array with 64 azimuthally arranged Langmuir probes is presented as a new diagnostic tool for the investigation of drift waves. A parallel data acquisition system provides full spatio‐temporal data of azimuthally propagating waves. For both regular and turbulent states of current‐driven drift waves, the information provided by such space‐time patterns is compared with results obtained from conventional two‐point correlation methods. The probe array allows one to directly estimate the time‐averaged wave number spectrum. In a turbulent state, the spectrum yields to a power law of S(k)∝k−3.6±0.1.