Observation of Hypervelocity Dust in Dense Supersonic Plasma Flows: Physics and Applications

Synthetic diamond and graphite dust powders with a wide range of sizes, from a few to several tens of microns in diameter were accelerated to velocities up to 4 km/s in vacuum by plasma jet produced in a coaxial gun. Some of the key features of the plasma flow are high density, of the order of $1022$ $m−3,$ low ion and electron temperatures, of only a few eV, and good collimation over a distance of $≈2 m$ due to confinement by the self‐generated magnetic field. The main features of this plasma‐drag acceleration technique are presented and discussed. From basic science point of view hypervelocity dust is useful for studying the physics of dust interaction with energetic plasma flows at microscopic level. In physical applications, it has been proposed to use hypervelocity dust for diagnostic or control of magnetically confined fusion plasmas. In engineering, hypervelocity dusty plasmas are extensively employed in industrial processes involved in the processing of surfaces.