Effect of cathode configuration on 30 kWe arcjet electrical characteristics

This paper compares the electrical characteristics of a 30 kWe arcjet for four cathode tip geometries. The electrical behavior of various cathode configurations is characterized by examining engine operation over a range of power levels (20 kWe - 30 kWe), current levels (200 A - 300 A) and geometric arc lengths (0.85 cm - 1.81 cm). Preliminary results indicate that tip geometry does not affect arc current or engine power when plotted as a function of geometric arc length, that at a fixed power the current level can be expected to drop as the arc grows in length due to erosion, and that any long duration test will require adjustment of the power source to maintain a constant power level.