Electrostatic Probes for Studying Transport Properties in Tokamak Plasmas

Electrostatic probes for measuring the boundary plasma in tokamaks are reviewed and presented. Transport properties in JFT‐2, the ion temperature and the magnetic surface in JFT‐2M and floating potential fluctuations during the strong additional heating in JT‐60 are measured by several types of electrostatic probe the above‐mentioned purposes. The Langmuir probe including the double probe is applied to measure the spatial profile of boundary plasma in JFT‐2. The ion sensitive probe, the rotating cylindrical double probe, the asymmetric double probe and the differential double probe are applied to measure the ion temperature and magnetic surface in JFT‐2M. The reciprocating Langmuir probe applied to JFT‐2M observes the potential and density fluctuations and a new type probe is proposed for the quick diagnostic of core hot plasmas as a development of this probe. The fluctuation observed in JT‐60 is identified to be the ion cyclotron instability of the hot plasma caused by the strong anisotropy of the ion distribution function (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)