THE TIME-DOMAIN TRIPLE-PROBE METHOD

A new Langmuir‐probe technique based on the triple‐probe method is being developed to provide simultaneous measurement of plasma temperature, potential, and density with the temporal and spatial resolution required to accurately characterize plasma turbulence. When the conventional triple‐probe method is used in an inhomogeneous plasma, local differences in the plasma measured at each probe introduce significant error in the estimation of turbulence parameters. The time‐domain triple‐probe method (TDTP) uses high‐speed switching of Langmuir‐probe potential, rather than spatially separated probes, to gather the triple‐probe information thus avoiding these errors. Analysis indicates that plasma response times and recent electronics technology meet the requirements to implement the TDTP method. Data reduction techniques of TDTP data are to include linear and higher‐order correlation analysis to estimate fluctuation induced particle and thermal transport, and relationships between temperature, density, and potential fluctuations.

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