Multi-anode photomultiplier tube as a tool for spatio-temporal measurements in a plasma

Measurements of fast phenomena in the vicinity of a limiter inserted into a linear plasma column are shown in this work. The results were conducted at the plasma generator PSI-2 (Humboldt Universitaet zu Berlin, Germany) which provides a stationary plasma produced in a DC arc discharge. The plasma near a tungsten limiter was imaged on a photomultiplier tube equipped with 16 anodes. The photomultiplier array was being attached to oscilloscopes. In comparison with fast cameras this arrangement is inferior with respect to spatial resolution but superior with regard to temporal resolution which is more important in the present context. Two different structures with enhanced photon emission regions were investigated. On the one hand the rotation of the plasma column could be seen, with and without limiter. On the other hand, when immersing limiters inside the column structures with a high photon emission travelling radially into the shadow downwards the limiter were investigated. These investigations deal with basic questions, they could help to understand the anomalous transport in linear devices in general and the transport in plasma shadows behind limiters in particular.