A NEW SCHEME FOR LANGMUIR PROBE MEASUREMENT OF TRANSPORT AND ELECTRON-TEMPERATURE FLUCTUATIONS

A new scheme to extend the triple Langmuir probe technique for the measurement of electron temperature fluctuations and the fluctuation-driven transport has been developed. The extension is aimed at reducing the phase delay error introduced by finite probe tip separations in standard triple-probe method. The modified triple-probe scheme provides a more reliable measurement of the temperature fluctuations for a proper interpretation of the density and potential fluctuations and the transport measurement from Langmuir probe data. New results on fluctuations have been obtained from Phaedrus-T and TEXT-U tokamaks.