Measurements of plasma potential and electron temperature by ball-pen probes in RFX-mod

摘要

The ball-pen probe (BPP) is an innovative electric probe for direct measurements of the plasma potential. This probeudwas developed in IPP Prague and it is based on the Katsumata probe concept. Combined measurements of the plasmaudpotential by a BPP and floating potential by a Langmuir probe provide also the value of the electron temperature. Firstudtest of the BPP on the RFX-mod reversed field pinch in Padova has been performed in November 2006. The BPP head,udmade of boron nitride, is equipped with four graphite collectors, which are positioned at four different radial positions hudinside four shafts hollow into the probe head. The radial profile of the plasma potential and also the electronudtemperature were measured.