Physical measurements on heavy-current discharges

An understanding of heavy-current discharges entails extensive measurement of the plasma. A review is given of some measurements with particular reference to the thermonuclear apparatus Sceptre III, although one of the categories of measurement is applicable to any hot gas containing deuterium. Emphasis is placed on instrumentation and on the physical basis of measurement. Limitations of and improvements to the methods and the modifications to be anticipated when the plasma temperature rises are indicated. Results of measurements not previously published, such as those on discharge stability and energy loss, are included. Although few of the measurements are completely reliable, several independent methods of measurement can yet provide a self-consistent and hence more trustworthy result. New methods of measurement are desirable to extend the present range.