| 摘要 |
PURPOSE:To stabilize operation while suppressing parasitic mode oscillation by forming an electron beam interactive with a high frequency electromagnetic field of plural layer hollow beams having different cyclotron orbital centers. CONSTITUTION:An electron beam is constituted of two-layer hollow beams having different cyclotron orbital centers while selecting a TE051 mode in an operating mode whereby every of two-layer hollow beams is no made as to strongly combine with a high frequency electric field. On the other hand, to TEmnl generating at this moment a parasitic mode oscillations, the combination of the other electron beam with the high frequency electromagnetic field is extremely weak due to the character is electromagnetic field distribution of TEmnl mode even when either electron beam of the two-layer electron beams is strongly combound with the high frequency electromagnetic field. Accordingly, it does not lead to oscillation in the parasitic mode. |
