THz源是THz波应用的关键，探讨新机理提高辐射性能具有十分重要的意义。在国家自然科学基金资助下，对高亮度ps级超短电子束产生THz的SP相干辐射进行了研究，已发表论文31篇，其中SCI收录7篇，EI收录11篇，主要成果有：(1)首次建立了可同时测试THz波功率和频率的实验系统；(2)在国内首次利用超短电子束完成了产生THz波的实验;(3)提出了两段式光栅结构提高SP相干辐射的方法。本项目提出以行波和返波高频结构组成的级联注-波互作用系统为基础，开展双电子注驱动的级联THz扩展互作用器件的机理研究，探讨在返波段产生的THz波耦合到行波段中完成THz放大的机理。拟对圆形电子注与级联高频结构的注-波互作用过程进行线性与非线性理论分析，研究高频结构、电子注、耦合装置等参数对输出特性的影响，开展高频冷测和原理性实验，掌握发展宽频带紧凑型THz真空电子器件关键技术，为THz集成真空器件提供理论指导。

Terahertz (THz) Source is a key part during THz wave application, and developing novel mechanisms for improvements of THz performances are very important. With the support of national nature science foundation of China, the THz coherent Smith-Purcell radiation emitted by high brightness picosecond (ps) ultra-short electron beam is studied. The research papers of 30 articles are published, in which 7 articles are indexed by SCI and 15 articles are indexed by EI. The main achievements are listed as following:(1) The experiment system for synchronous measuring THz power and frequency is set up at the first time;(2) The experiment of emitted THz wave produced by ultra-short electron beam is performed at the first in China;(3) The improvement of THz SP radiation enhanced by two-section grating is presented and verified. The base on cascade beam-wave interaction system constituted by traveling and backward high frequency structure (HFS) is presented in this project, the mechanism researches of cascade extended interaction device driven by two electron beams will be conducted. The physical mechanisms of THz wave generating from backward HFS and amplified in traveling HFS are to be studied. In this project, the linear and nonlinear theoretical analyzes of beam-wave interaction of circular electron beam with cascade HFS will be studied. The varied parameters of HFS, electron beams and coupling equipment effect on output characteristics are researched. Moreover, the high frequency cold test and principle tube experiments are developed. Through this study, we should hold the key technologies of developing width band and compact THz electron device. On the other hand, we can provide the theoretical and technological supports for developing integrated THz vacuum device.