Electron beam focusing features in a plasma electron source under forevacuum pressures

Features of focusing electron beams generated by a forevacuum plasma source under pressures of 10–30 Pa are investigated and the principle possibility of obtaining submillimeter beams is demonstrated. A beam power density of 10$^5$ W/cm$^2$ is reached at an electron beam diameter of 0.6 mm. The obtained beam parameters offer opportunities for precision electron beam processing of dielectric materials, including hightemperature alumina ceramics.