Installation of the room temperature solid state pellet injector for investigation of runaway electrons at the COMPASS tokamak

The aim of the article is a description of the first realization of the pellet injection experiment at the COMPASS tokamak. In order to study the interaction of the solid state materials with runaway electrons in tokamaks, the room temperature solid state pellet injector (RTSP) was borrowed from the ASDEX Upgrade tokamak and reinstalled at COMPASS. Firstly, RTSP was characterized at the test bed at Max Planck Institute in Garching and important quantities for successful reinstallation such as pellet divergence and propellant gas throughput were measured. Obtained results were taken into account during design and assembly of the dedicated vacuum system needed for the RTSP operation. The RTSP system was operated in the runaway electron campaigns at the COMPASS tokamak and reliable delivery of graphite pellets (2x1.5 mm) was demonstrated. The preliminary analysis of the pellet injection impact proving successful pellet firing into a plasma, is given.