Amplification of output microwave power in low-voltage virtual cathode oscillator under external force

It is well known that virtual cathode (VC) oscillators, or vircators, are promising high-power microwave generation sources. Most experiments show that this type of electronic devices demonstrate record output microwave power¹. On the other hand vircators are characterized with relatively low efficiency. One way of efficiency gain is a controlling the beam dynamics in vircator by the external force. A number of works devoted to the problem of non-autonomous vircator phase locking2 and output power increasing show that we can consider VC oscillator not only as microwave generator, but also as a perspective amplifier3. In this work we have carried out the theoretical and experimental analysis of processes of amplification taking place in vircator under external force. The basic model of our reseacrh is the non-autonomous low-voltage vircator4. We have begun our research from the analysis of simple theoretical model of modulated electron beam with VC. We continued our investigation in the framework of onedimensional numerical simulation according to particle-incell method5. The results of our theoretical treatment of intensive beam dynamics in virtual cathode oscillator show the ability of amplification and efficiency arising in vircator due to electron beam modulation with external signal. These results are in a good qualitative agreement with the experimental results obtained in laboratory model of low-voltage vircator.