Generation of hypervelocity plasma pulses using an electrothermal accelerator

Hypervelocity plasma pulses are generated with the help of an electrothermal accelerator and used for surface treatment and modification of metals and alloys. The paper presented here deals with the electrothermal accelerator (ETA) itself as the necessary plasma source. After a short description of the standard ETA and its energy storage system, the first part of the paper gives results of the experimental investigations on the plasma pulse. Since the surface modification is strongly dependent on the interaction of the target material with the impacting plasma pulse, it is important to know its characteristics. Essential parameters, such as jet velocity, dynamic pressure, pulse duration and transferred electric energy were measured. The changes of these pulse parameters were connected to the more easily controlled input parameters, such as the charging voltage and the amount of additive used for plasma seeding. This investigation helps to adjust and optimize the electrothermal accelerator more precisely to the needs of surface treatment. The second part of the paper discusses far reaching changes of the design and the operation of the ETA in order to further improve its capabilities in generating hypervelocity plasma pulses. For two of these concepts-the use of clustered capillaries and the generation of an open arc jet-first demonstration experiments have already been set up