The peculiarities of an operating mode close to the critical in the smooth anode magnetron

The conventional (classical) magnetrons generate with the operating magnetic field H>H/sub c/ (c is the critical magnetic field). At the same time, oscillations of the cyclotron-frequency type are described. These oscillations take place in the magnetrons with smooth-bore anode with H/spl sim/H/sub c/. It is noted in the literature that this type is of no practical interest. On the other hand, over the last decades significant results were obtained on the millimeter wave generators-the surface wave magnetrons (SWM) which operate directly with H/spl sim/H/sub c/ and with the very high experimentally confirmed values of efficiency. Probably, in these devices some other mechanism of electron-wave interaction is realized, which differs from the traveling wave type oscillations in the conventional magnetrons. In order to understand this mechanism, it is seems necessary to analyze in more detail the processes in a smooth anode magnetron with H/spl sim/H/sub c/. Just this topic is the aim of the work.