№4 (51), 2019. TECHNOLOGY AND EQUIPMENT OF MECHANICAL AND PHYSICAL-TECHNICAL PROCESSING

A theoretical model has been developed for the formation of a beam of fast gas atoms by a grid immersed in plasma under a negative potential U ~ 5 kV. It was shown that the atoms energy is continuously distributed from zero to the maximum eU achieved at a gas pressure po ~ 1 Pa, when the charge exchange length of ions c is equal to 2d, where d is the width of space charge sheath at the grid surface. With increasing pressure p, the length c and the maximum energy of atoms decrease by p/po times, and the atomic flux density increases by the same amount. When replacing the flat grid by a grid with a concave surface, the ions and fast atoms trajectories being perpendicular to the grid converge on the surface of a tool under treatment, which allows a noticeable increase in its heating temperature.