The New High-power Radial Klystron Oscillator To Explore

Several new styles of radial klystron oscillators are studied theoretically and numerically. These new members include: the radial klystron oscillator with foldaway-concentric cylindrical cavity, the radial reflex klystron oscillator with virtual cathode and radial reflex klystron with open foldaway-concentric cylindrical cavity. The mechanism of interaction between radial electron beam and electromagnetic wave fields is also analyzed in-depth.The kinematics of electron beam within the radial diode areas and interaction structures are studied by using one-dimension model, the energy exchange process between electrons and high frequency field is also analyzed. The improved microwave output power and efficiency are obtained.(1) The radial klystron oscillator with foldaway-concentric cylindrical resonant cavity is researched firstly. Compared with the traditional TTO, its start-up current is much less, and its larger cylindrical volume allows a higher space charge limit current. Therefore no guiding magnetic field is required. The input electrical power at the given voltage is increased due to the larger emitting surface of the radial structure and the space-charge effects are also relatively small. The start up and linear growth process of the microwave within the foldaway-concentric cylindrical resonant cavity are analyzed based on the one dimensional model firstly, then a 2.5-D PIC code is employed to study the nonlinear interaction. It is shown that a peak output power of 6GW with frequency of 1.6GHz can be extracted from the well-designed radial klystron oscillator with foldaway-concentric cylindrical resonant cavity with the diode voltage 380kV and the electron beam of 38kA.(2) Then the radial reflex klystron oscillator with virtual cathode is studied. This is also a high power microwave device with no requirement of a guiding field. The feed-back provided by the reflected electron beams reduce the start-up current and the start-up time in a vircator, while the existence of klystron cavity improves the extracting efficiency, hence the radial reflex klystron oscillator with virtualcathode combines the advantages of both devices, becomes a compact, efficient set. This new radial reflex klystron oscillator with virtual cathode is designed and simulated by 2.5-D PIC code. Simulation results show 2.5 GW output power with a frequency of 1.25GHz can be generated with an input of 620kV voltage, DC input power of 10.5GW electron beam.(3) The radial reflex klystron with an open foldaway-concentric cylindrical resonant cavity integrates the resonant cavity and reflex cavity within one foldaway coaxial cavity, so it is a very compact high power microwave device. The radial high current forms the virtual cathode in the reflected high frequency field, which further modulates the emitted electron beam. The simulation results of the 2.5-D PIC code for this new structure are presented. A 2.5 GW peak output power with the frequency of l.3GHz is generated with the input of 625kV voltage,DC input power of 18GW...