Advanced probe measurements of electron energy distribution functions in CASTOR tokamak plasma

Langmuir probes are known for their ability to provide local measurements of very important plasma parameters, namely the plasma potential, the density of the charged particles and the electron energy distribution function (EEDF). The correctness of using the probes under adverse conditions, such as presence of magnetic fields or high plasma temperature is still being questioned. In this paper we report the application of the first-derivative Langmuir probe method for processing the electron part of the volt-ampere (IV) characteristics measured in the CASTOR tokamak plasma. First results of EEDFs at different radial positions in the edge plasma are presented and the values of the plasma potential, electron temperature and electron densities are estimated. The applicability of the first-derivative Langmuir probe method in strongly magnetized, high temperature tokamak plasmas is discussed