Research On A High Power Microwave Cerenkov Oscillator Driven By Sheet Electron Beam

The Cerenkov-type oscillator is one of the important types of the long pulse and repetition frequency high power microwave(HPM)source due to its high power,high efficiency and high repetitive rate.Limited to the device power capacity,there are so many studies on the Cerenkov-type HPM oscillator operating in the low frequency regime,however researches on high operation band such as K-band and Ka-band are scanty.High-power microwave source driven by sheet electron beams is promised to have higher current by increasing the size of the sheet electron beam.In this way,the injection power of microwave source,the area of beam-wave interaction and the space of the output cavity are increased,which can preferably solve the problem of power capacity.Based on the above discussion,the Cerenkov-type HPM oscillators driven by sheet electron beam,which respectively operating on X-band and K-band are proposed and designed in this paper.In order to improve the efficiency of simulation optimization,a research method is proposed that the large caliber coaxial Cerenkov-type HPM oscillator taken as a transition model,which is equivalent to that of the planar SWS by using the similarity between the planar SWS and the large caliber coaxial SWS.The large caliber coaxial Cerenkov-type HPM oscillator is simulated by 2.5-D particle in cell(PIC)code to get higher work efficiency.Then according to the result,the device driven by sheet electron beams is simulated with investigated by 3-D PIC code.The method can improve the efficiency of researching the HPM Cerenkov oscillators driven by sheet electron beams.The results are listed as follows.1.The equivalent research method of the HPM Cerenkov Oscillator driven by sheet electron beams is analysed and validated.The similarity between the planar SWS and the large caliber coaxial SWS is confirmed in the aspects of the geometric structure and the working mode preliminary.After that,the dispersion relationships of the two SWSs are investigated by the finite element code.As for the X-band devices,when the radius of the large caliber coaxial SWS is larger than 50 mm,the dispersion curves of the two SWSs are almost overlapping.Mean while,the preliminary simulations of the device driven by sheet electron beam and the large caliber coaxial device are carried out,which are in good agreement.In that case the method that the device driven by sheet beams analyzed after the large caliber coaxial device is proved viable.2.A research of the X-band large caliber coaxial Cerenkov-type HPM oscillator is investigated with a 2.5-D PIC.The simulation results show that,the power conversion efficiency can reach 34.4%,corresponding to the output power of 7.3 GW,the saturation time of 25 ns and the resonant frequency of 11.9 GHz,under the condition of the voltage of 486 kV,the current density of 1.0 kA/cm2,the current of 43.8 kA and the applied magnetic field of 3.0 T.3.Based on the above results,an X-band Cerenkov-type HPM oscillator driven by sheet electron beam is investigated with a 3-D PIC.The simulation results show that,the power conversion efficiency can reach 26.1%,corresponding to the output power of 0.3 GW,the saturation time of 19 ns and the resonant frequency of 11.9 GHz,under the condition of the voltage of 486 kV,the current density of 1.0 kA/cm2,the current of 2.4 kA and the applied magnetic field of 3.0 T.4.A K-band large caliber coaxial Cerenkov-type HPM oscillator is investigated with a 2.5-D PIC.The simulation results show that,the power conversion efficiency can reach 38.8%,corresponding to the output power of 1.65 GW,the saturation time of 21 ns and the resonant frequency of 25.48 GHz,under the condition of the voltage of 196 kV,the current density of 1.0 kA/cm2,the current of 21.61 kA and the applied magnetic field of 3.0 T.5.Based on the above results,a K-band Cerenkov-type HPM oscillator driven by sheet electron beam is investigated with a 3-D PIC.The simulation results show that,the power conversion efficiency can reach 23.3%,corresponding to the output power of 27 MW,the saturation time of 22 ns and the resonant frequency of 25.8 GHz,under the condition of the voltage of 196 kV,the current density of 1.0 kA/cm2,the current of 600 A and the applied magnetic field of 3.0 T.6.The preliminary experimental designs of the device driven by sheet electron beams and large caliber coaxial device are developed.The guiding magnetic field excitations systems of the two devices are designed by using the simulation software,which can perferably meet the requirement of the configuration of the magnetic.The Cerenkov-type HPM oscillator driven by sheet electron beam is designed,which set a good foundation for the experimental research.