Current distribution during conduction and POS opening on GIT8

The concept of the multi module pulsed power system using the inductive energy storage (IES) technology may be developed on a base of one of two possible plasma opening switch (POS) designs. First is the multi POS design with the number of the switches being equal to the number of the modules. The main advantages of this design are the possibility to perform the full scale investigation of the single module prototype including the POS before the total system will be built, and the possibility to increase the power of the system by adding some number of the well known elements. The main disadvantage of the multi POS design seems to be the jitter in the switch openings-the problem which is not solved at present. The second, single POS design, presumes one POS switching the energy from all the modules into the load. The main advantage of the design is the absence of the POS synchronization problem. In the same time the single POS design requires building of the total system before the POS could be tested resulting in a risk of worse opening or some other problems which may appear at increased POS current level. The GIT4-GIT8 facilities at HCEI represent a test bed allowing investigation of the single POS design at successively increasing POS current (2.5-5 MA). The goal of the experiments described was to clear the current distribution in the switch region on GIT8 and to determine possible restrictions which could limit the application of the given single POS design.