A Two-Stage Launcher–Accelerator Working on Hydrogen

Abstract

The main advantage of light-gas launchers is the possibility of achieving high velocities of projectiles (up to several kilometers per second). The efficiency of a launcher depends on the molecular weight, pressure, and temperature of the working gas, which determine the sound velocity in the gas. The required gas characteristics can be achieved by an adiabatic compression of the gas or by its heating with an electric arc. A disadvantage of the first method is the necessity of compressing the gas to a very high pressure (>2 GPa) in order to obtain the required temperature. In the second case, the gas in a closed volume must be heated to a temperature of several thousand degrees in order to raise its pressure, thus causing the strong thermal erosion of the launcher's elements. A two-stage launcher that combines preliminary adiabatic compression of the working gas (hydrogen) and its subsequent heating with an electric arc has been developed at the Institute of the Problems of Electrophysics. This design ensures highly efficient launcher operation (the efficiency of energy transfer from the arc to the gas is close to 100%) and allows the maximum gas temperature to be decreased. The operating characteristics of the combined launcher were studied, and the parameters of an electric arc in hydrogen with a concentration of (1.5–3.3) × 1022 cm–3 and currents of hundreds of kiloamperes were determined. The description of the facility design and the results of its experimental tests are presented.