Investigation of a coaxial plasma jet accelerator

We report the results of an investigation of the main energy parameters of a plasma jet from a coaxial accelerator with a conical insert in the charge-formation region. We have obtained the dependences of the pressure and the jet diameter of the deuterium plasma on the distance to the accelerator, as well as on its length and the voltage polarity at the electrodes. It is shown that plasma jet energy is a quadratic function of voltage. Among all tested modifications, an accelerator with a length not exceeding 220 mm, a negative polarity of the voltage at the central electrode, and a focusing conical insert at the beginning of the outer electrode is found to be most effective. At the source output, a deuterium plasma with an ionization front velocity exceeding 100 km/s and a pressure exceeding 1 MPa is obtained. We describe a method for measuring the jet pressure with the help of a deflecting screen and an FLIR SC7300M infrared camera.