Thomson scattering at Pilot-PSI and Magnum-PSI

A robust and sensitive Thomson scattering (TS) system has been developed for the high density low temperature plasma in the linear plasma generator Pilot-PSI, which routinely and reproducibly measures electron density and temperature profiles along a detection chord of 25 mm with a spatial resolution of 0.6 mm. The capabilities of the system are illustrated in this paper by a selection of new results from the research program at Pilot-PSI. TS data are presented that demonstrate the present plasma density record in Pilot-PSI: 5 × 1021 m−3 at a temperature of 3 eV. TS measurements in front of the target are combined with ion saturation current data to determine plasma velocities of 4–5 km s−1, which shows that heat convection is dominating over conduction. Single shot operation of TS is also possible, which is demonstrated by measurements revealing a rotating filamentary return current channel to the source anode. Finally, the TS system upgrade that will provide real time feedback of electron density and temperature in the larger plasma generator Magnum-PSI is discussed.