부산대학교 도서관

In the edge region of magnetised fusion experiments hitherto mainly cold probes were used in order to determine the plasma potential and thereby parameters like electric field turbulence. However, this method causes problems when the electron temperature varies and when the electrons are drifting. We have therefore used electron-emissive probes in (i) the tokamak ISTTOK in Lisbon, Portugal, (ii) the CASTOR tokamak in Prague, Czech Republic, and (iii) the TJ-II stellarator in Madrid, Spain. Our method has the advantage that in principle the electron emission current compensates temperature variations and electron drifts. We discuss the applicability, the advantages and the limits of emissive probes for measurements of the plasma potential and the electric field, taking into account especially the effect of a space charge around the probe wire, formed by the emitted electrons. [ABSTRACT FROM AUTHOR]