Hypervelocity Dust Storm Launched With a Coaxial Plasma Gun

A dust storm consisting of carbon grains accelerated to speeds of up to $ \sim$3 km/s has been launched by a plasma jet produced in a coaxial gun. Diamond and graphite powders with grain radii of 0.5–30 $\mu\hbox{m}$ have been used. A distinctive feature of this plasma accelerator is that it can use different types of gases and can operate with microparticles having a large range of sizes. Deuterium gas and carbon dust are chosen to be compatible with fusion plasmas as a diagnostic tool. The operating voltages of the coaxial gun are between 5 and 10 kV, and the maximum measured discharge current is 250 kA. High-speed imaging of the plasma jet accelerated by the $J \times B$ force, and exiting the gun at 34 km/s, shows a good collimation of the flow for about 1.5 m before it diverges inside a large vacuum tank.