Nonconventional Magnetron as the Cherenkov Generator With a Gyroresonance: Electron-Wave Synchronism Conditions and Experiments

Advancement of magnetrons into the short-wave part of the millimeter band and further into the terahertz range is hampered by a number of objective factors. Overcoming these limitations, the researchers tried to modify the tubes design, achieving the maximum possible increase in the size of the interaction space, with comparable or significazantly reduced operating fields. This was partially realized when creating magnetrons on spatial harmonics. However, the formulas obtained from the conventional concepts of electron-wave synchronism in crossed fields are inaccurate for such generators. And numerical estimates not having an adequate analytical theory often are incapable to indicate ways to improve tubes. As the experiment results show, an analytical model taking into account possibility of gyroresonance describes the physical processes in such magnetrons with sufficient accuracy and its use essentially simplifies their development, ensuring the choice of generator parameters and operating regimes. In fact, these magnetrons can be considered as Cherenkov generators with gyroresonance. Interaction with an electromagnetic wave under synchronism conditions, including the orbital component of the electron velocity, provides a noticeable increase in the dimensions of the interaction space with the close operating fields as compared to magnetrons using purely drift synchronism. Accordingly, good prerequisites are created for further shortening of the operating wavelength, with the prospect of advance into the terahertz range of oscillations.