Generation of electron beam plasma near the surface of conductive and dielectric disks

Beam-plasma formations that occur near the surface of metal disks and metal disks with dielectric coating when irradiated with a continuous or intermittent electron beam were experimentally investigated. As a plasma-forming gas, air was used, the pressure of which varied within the range of 10-1 - 2 · 101 Torr. As a result of processing of optical images of Beam-plasma formations, the influence of gas pressure on the geometry of plasma clouds and their location relative to the disk surface was found. The study of the transient charging/discharging of disks showed that the front and rear edges of the electrical signal (disk potential relative to «earth») from the disc with a dielectric coating differed significantly from the shape of the fronts from uncoated metal disks.