Study on the characteristics of different plasma ignition schemes

Plasma ignition mechanisms have always been the central issue in the electrothermal-chemical (ETC) launch technology. Generally, there are two types of ignition schemes, namely, the axial discharge scheme and the radial discharge scheme, and the two schemes are supposed to have different ignition characteristics. This work is devoted to study the features of different plasma ignition schemes in the ETC launch devices. A capillary discharge setup and a gap discharge setup are utilized in the experiments to represent the axial and radial discharge ignition schemes, respectively, and three types of propellants are used in the study. Using the measured data in the experiments, plasma heat fluxes are solved by a plasma-propellant interaction model. In addition, the propellant surface conditions are investigated by a scanning electron microscope after the plasma ignition experiments. The surface conditions of propellants in different ignition schemes display distinct features, which are analyzed to shed light on the characteristics of different ignition schemes and the responses of different propellants. Results are supposed to help in interpreting the plasma-propellant interaction mechanisms in different ignition schemes and provide references for the optimization design of plasma ignition installations in the ETC launch devices.