Kirichenko L. А. UkraineKharkiv O.Ya. Usikov Institute for Radiophysics and Electronics of the National Academy of Science of Ukraine, ul. Akademika Proskury, 12, Kharkiv, 61085, Ukraine Ведущий инженер ИРЭ НАНУ Author's articles MAGNETIC FOCUSING SYSTEM FOR INTENSE ELECTRON BEAMS OF SUBMILLIMETER CLINOTRONS