To Guide The Exploration Of The Magnetic Field Of High Power Microwave Source

A brief description of the light high power microwave(HPM) sources are given. As pointed out earlier, those sources eliminate the need for a heavy external magnet. Two HPM sources Magnetically Insulates Line Oscillator(MILO) and the Reltron have been researched and improved. Finally, a new high power microwave source, the axial acceletron is presented in this paper.We have made a detailed theoretical analysis on the beam-wave interaction in MILO and derived electron beam bunching theoretically. A compact and simplified nonlinear equation set on the evolution of the radiation field is also derived. Two-dimension fully electromagnetic Particle-in-cell (PIC) simulation is used to study the designed by Phillips Laboratory. Specially, we have researched the effect of the changing the parameter of MILO. High power and high frequency MILO was made the design an consideration. In terms of the PIC simulation, the output power of 1.5GW at C band and 200MW at X band in MILO have been obtained. The MILO works at 500MW C band driven by a 400KV, 60KA electron beam has been done in experiment.A new coaxial-structure Super-Reltron was explored to develop a low-impedance high-power microwave tube. This source will have a power output of about 2.5GW with 25% efficiency at 5.2GHz. The input modulate voltage is 125kV and the post-accelerating voltage is 600kV. Because of using the coaxial structure, the diode impedance may be reduce to a few Ohms, which allow large input and output powers. Numerical simulations show the frequency is approximately inversely proportional to the length of screen. In addition, it is shown that the scaling of output power is proportional to I², when the current is less than the space charge-limit.A new high power microwave source, the axial acceletron is presented in this paper. Compared with the radial accelectron, an acceleration region is added after the diode/oscillator and radial acceleration is change to axial acceleration. The bunching and radiation of the electron beam in the device are investigated. It is found that the electron beam may approach ideal bunching. High power microwave pulses with tunable frequency can be generated by post-accelerating the electron beam and carefully designing the extraction cavity. In terms of the PIC simulation, the output power of 1.25GW at 2.2GHz and 480MW at 4.4GHz in axial acceletron have been obtained.