A technology for generating intense annular electron beam with variable beam radius and its application
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摘要: 束半径可调的强流环形电子束在跨波段跳频高功率微波产生器件中有重要应用。提出了一种改变外加引导磁场位形从而改变环形强流电子束半径的技术。该技术的核心部件由环形阴极、阳极、电子束转移通道、电子束传输通道和三段螺线管组成。当三段螺线管的通流的电流大小不一样时,该螺线管系统就能产生不同位形的磁场。在粒子模拟中,当三段螺线管的通流电流大小分别为1025 A、107 A、107 A和300 A、300 A、0 A时,螺线管产生两种不同位形的磁场,实现电子束半径的改变。从单粒子运动理论出发,本文推导出电子束在梯度磁场引导下的运动轨迹表达式,解释了电子束半径在梯度磁场下变化的原理,还研究了梯度磁场的斜率和极差对电子束轨迹的影响。在跨波段器件仿真中,X波段输出功率为1.6 GW,频率为8.2 GHz,效率为40%;Ku波段输出功率为1.5 GW,频率为14.4 GHz,效率为38%。Abstract: Intense annular electron beam with variable beam radius has important applications in high power microwave (HPM) generation devices with cross-band frequency hopping. This paper proposes a technology of changing the radius of annular electron beam based on the adjustment of the externally guided magnetic field. The core components of the technology include an annular cathode, an anode, an electron beam transfer channel, two transmission channels and an external guide magnet (a three-segment solenoid) system. When the current of the solenoid differs, the solenoid system can generate different magnetic field distributions. In the particle-in-cell (PIC) simulation, when the currents of the three segments are 1 025 A, 107 A, 107 A and 300 A, 300 A, 0 A respectively, the solenoid generates two magnetic fields to achieve the change of the electron beam radius. Based on the theory of single particle motion, this paper deduces the expression of the trajectory of electron beam guided by the gradient magnetic field, explains the principle of the electron beam radius variation under the gradient magnetic field, and investigates the influence of the slope and range of the gradient magnetic field on the electron beam radius. In the cross-band HPM devices simulation, the output power of X-band is 1.6 GW, the frequency is 8.2 GHz, and the power efficiency is 40%. The Ku-band has achieved a power output of 1.5 GW, a frequency of 14.4 GHz, and a power efficiency of 38%.
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Key words:
- high power microwave /
- slow wave structure /
- cross-band /
- frequency hopping
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表 1 电调节变半径二极管参数
Table 1. Parameters of electrically regulated variable-radius diode
(mm) Ra Rc RX WX Lac Lt RKu 48 28 54.5 12 22 14 31.5 表 2 螺线管绕制参数
Table 2. Solenoid parameters
order lateral turns axial turns lateral extra turns axial extra turns 1 10 25 5 10 2 10 51 5 10 3 13 30 7 10 表 3 反射器的结构参数
Table 3. Structural parameters of the reflector
(mm) Wb Lup Ldn Dup Ddn Rb 12 4 11 11 6.5 54.5 -
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