GENERATION OF HYPERVELOCITY PLASMA PULSES USING AN ELECTROTHERMAL ACCELERATOR

Hypervelocity plasma pulses are generated with the help of an electrot hermal accelerator and used for surface treatment and modification of metals and alloys. The paper presented here deals with the electrother mal accelerator (ETA) itself as the necessary plasma source, After a s hort description of the standard ETA and its energy storage system, th e first part of the paper gives results of the experimental investigat ions on the plasma pulse. Since the surface modification is strongly d ependent on the interaction of the target material with the impacting plasma pulse, it is important to know its characteristics. Essential p arameters, 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 paramete rs, such as the charging voltage and the amount of additive used for p lasma seeding. This investigation helps to adjust and optimize the ele ctrothermal accelerator more precisely to the needs of surface treatme nt. 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 c apabilities in generating hypervelocity plasma pulses. For two of thes e concepts - the use of clustered capillaries and the generation of an open are jet - first demonstration experiments have already been set up.