低磁场无箔二极管中阴极爆炸发射均匀性研究

High power microwave (HPM) can be used as an important directed energy weapon. O-type HPM generators, including the relativistic backward wave oscillator (RBWO), have been given special attention due to their advantageous performances such as large power capacity, high conversion efficiency and good repetitive operation ability. To promote the practicality of HPM technology, O-type HPM generators operating with low guiding magnetic field has become a research hotspot since they have the potential of miniaturization. However, under low magnetic field, the explosive emission cathode (EEC), which is used to generate the intense relativistic electron beam, tends to have bad emission uniformity, and this may significantly affect the performance of O-type HPM generators, lowering their output microwave power and worsening their operation stability. The bad emission uniformity of EECs has become a crucial bottleneck which limits the practicality of O-type HPM generators operating with low magnetic field. This project wants to make an effort to solve this problem. To do so, various methods, including theoretical analysis, numerical simulation and experimental research, will be adopted. First, the factors influencing the emission uniformity of EECs will be systematically researched, and the physical reasons worsening the emission uniformity of EECs under low magnetic field will be uncovered. Second, the influence of cathode emission uniformity on performance of O-type HPM generators, especially the RBWO, will be analyzed in detail. Third, the quantitative evaluation methods for cathode emission uniformity will be explored. And fourth, lots of efforts will be made to improve the emission uniformity of EECs under low magnetic field, including physical analysis, technologic exploration and experimental research. It is hoped that this project may provide technology support for efficient and stable operation of O-type HPM generators working with low guiding magnetic field.

高功率微波是当前竞相发展的一种重要的定向能武器技术。包括相对论返波管在内的O型高功率微波产生器件因输出功率和转换效率高、重复频率工作能力好等优点获得了广泛关注。为推动高功率微波技术的实用化，发展有利于实现轻小型化的低磁场O型器件是当前的一个重点研究方向。而在低磁场情形下，用于产生强流相对论电子束的爆炸发射阴极发射均匀性较差，从而使O型器件输出微波功率下降、工作稳定性变差，已成为限制低磁场O型器件实用化的重要瓶颈因素。本项目瞄准该问题，将综合采用理论分析、数值模拟和实验研究等方法，系统研究影响阴极爆炸发射均匀性的因素，揭示低磁场下阴极爆炸发射均匀性较差的物理原因，深入分析阴极发射均匀性对O型器件特别是相对论返波管工作性能的影响规律，探索阴极爆炸发射均匀性的量化评估方法，并通过物理分析、工艺探索和实验研究，研制在低磁场下发射均匀性较好的爆炸发射阴极，为低磁场O型器件的高效稳定工作提供支撑。

低磁场O型高功率微波器件是推动高功率微波技术轻小型实用化的重要研究方向，而爆炸发射阴极在低磁场下的发射不均匀性已成为制约器件发展的关键难题。本项目瞄准该难题，通过理论分析、数值模拟和实验研究，分析了低磁场下阴极发射均匀性较差的物理原因和影响阴极发射均匀性的关键因素，研究了阴极发射均匀性对相对论返波管工作的影响规律和机理，提出了环形阴极爆炸发射均匀性量化评估方法，探索了改善阴极爆炸发射均匀性的有效技术途径，设计并研制了发射均匀性较好的新型环形爆炸发射阴极。取得的主要技术成果为：（1）揭示了阴极表面形貌和空间电荷屏蔽效应是决定阴极爆炸发射均匀性的关键因素，阐明了低磁场条件下微点发射电流增大引起空间电荷屏蔽半径增大是导致阴极爆炸发射均匀性变差的物理原因；（2）揭示了阴极发射均匀性会对相对论返波管输出功率和工作模式产生明显影响，阐明了低磁场情形下该影响更加显著的原因；（3）提出了基于等离子体发光图像分析的环形阴极爆炸发射均匀性量化评估方法，给出了直接定量描述阴极发射不均匀程度的参数；（4）研制了碳化硅纳米线掺杂铝基复合材料阴极、表面微织构阴极、碳化硅改性石墨阴极等新型爆炸发射阴极，实验验证了其在低磁场下较普通阴极发射均匀性明显改善。上述技术成果深化了对爆炸电子发射和低磁场相对论返波管工作过程的认识，提出的阴极发射均匀性量化评估方法可以应用于环形爆炸发射阴极研究，研制的新型阴极可以应用于低磁场O型高功率微波产生器研究，具有重要的学术价值和应用价值。