The Thz Cyclotron Backward-wave Tube

THz technology is the hotspot research in the world, the THz radiation source is an important device, and it has important research value. Gyro-backward Wave Oscillators (Gyro-BWO), is a kind of fast-wave vacuum electronic devices based on electron cyclotron maser instability, can be used to generate high power and high efficiency electromagnetic radiation in THz wavelength range. The potential applications of the Gyro-BWO are momentous in some areas such as millimeter-wave radar, controlled thermonuclear fusion plasma heating and diagnostics, and directed energy weapons and material handling and so on.Gyro-BWO produce high power, high efficiency electromagnetic radiation in result of electron beam interaction with the backward wave. Using the interaction between electron beam and waves in Gyro-BWO, combined with the principles and characteristics of gyro-BWO, this paper designs TE0 3 mode of THz gyro-BWO, also does the theoretical analysis and numerical simulation of its starting current. With change of the voltage of electron beam, the external magnetic field, the interaction length and operation frequency, the vibration of starting current is numerically calculated. One has obtained a starting current of 1.86A with an operation frequency of 220 GHz, an external magnetic field of 8.55 T, an interaction length of 23 mm and a voltage of electron beam of 55 KV. In the range of operating frequency, the max efficiency of Gyro-BWO is about 20%, the result is: when the external magnetic field and the voltage of electron beam independently increase, the operation frequency increases and decreases. It also has significantly changed near the cut-off point.This paper uses the electromagnetic particle simulation software MAGIC to simulate the 220GHz Gyro-BWO. In the corresponding parameters, the influence of the external magnetic field, the voltage of electron beam, the electronic beam current on the output power and efficiency have been shown, and the operating frequency under different the parameters is analyzed in detail. Then do the relationship between the output power and efficiency and the interaction length. Finally, the analysis of output transition section is done. When the interaction length is 23 mm, the voltage of electron beam is 55 kV, the ratio of vertical and axes velocity is 1.5, the electronic beam current is 6A and the external magnetic field is 8.55T, the output power is 73 KW, and the interaction efficiency is 22.1%. Once the voltage of electron beam is up to 55 KV, the output power of the Gyro-BWO decreases and the external magnetic field increases, the efficiency is correspondingly reduced. When the external magnetic field range from 8.55T to 9.20T, the frequency changes from 214.47GHz to 222.21GHz,the bandwidth is 7.74GHz,the output power is more than 30KW; When the external magnetic field is 8.55T, the output power and efficiency of the Gyro-BWO increase with the voltage of electron beam rising from 45KV to 55KV, the frequency changes from 215.62GHz to 213.75GHz, the bandwidth is 1.87GHz, the output power is more than 49kW. Taking the above into account, tuning of high frequency is realized by changing the external magnetic field and the voltage of electron beam. So the Gyro-BWO with high output power and high efficiency is designed. These results provide a theoretical explain and simulation model for further experimental study.