A comparison of Langmuir probe techniques for measuring temperature fluctuations

Two techniques are applied and the results compared in the edge plasma of TEXT‐U to estimate temperature fluctuations. The first technique fits the measured current fluctuations from a double probe as a function of probe bias with several fitting functions to provide density, and temperature fluctuations but with no spectral information. The second method uses a triple‐probe technique to measure density, temperature, and floating potential as a function of time. The two techniques are in agreement to within estimated error limits and find T̃/T≊0.4–0.5 ñ/n both in the scrape‐off layer and in the main body of the plasma.