高功率微波等离子体放电研究进展  

High power microwave plasma discharge

作　　者：常超 Chao Chang(Advanced lnterdiscriplinary Technology Research Center, National Innovation Institute of Defense Technology, Beijing 100071, China;Key Laboratory of Physical Electronics and Devices of the Ministry of Education, Xi＇an Jiaotong University, Xi＇an 710049, China)

机构地区：[1]国防科技创新研究院前沿交叉中心,北京100071 [2]西安交通大学物理电子与器件教育部重点实验室,西安710049

出　　处：《科学通报》2018年第14期1390-1403,共14页Chinese Science Bulletin

基　　金：国家自然科学基金(11622542和51677145)资助

摘　　要：高功率微波(HPM)在科研、民用和国防领域具有广阔的应用前景.HPM具有瞬时高峰值功率达到数十亿瓦、脉宽从几十至数百纳秒的特点,随着HPM技术向高峰值功率、长脉冲和高重复频率发展,强电磁场击穿已成为限制HPM产生、传输及辐射系统功率容量的主要因素,是HPM技术进步面临的巨大技术挑战之一.本文综述了近20年来HPM输出窗真空及大气击穿、金属表面击穿等方面的国内外主要研究进展:击穿机理方面,国内外已对基本物理过程进行了定性描述,基本建立了二次电子倍增、表面气体释放及等离子体雪崩的动理学模型,但缺乏定量描述、实验数据支撑和等离子体能谱与密度的时空诊断.周期性表面、谐振磁场、表面氟化等物理和化学新方法已经成功运用到抑制击穿、提高功率容量的技术中,但离实用化还有差距.High-power microwave （HPM） has broad applications in scientific research, civil and military community. HPM has the character of peak power of tens of Giga-Watt and the pulse width from tens of to hundreds of nanosecond. The intense electromagnetic breakdowns in the HPM generation, transmission and radiation systems, seriously limit the HPM sys- tematic power capacity, and become the bottle neck of the HPM technology-development and the international technical challenge. In this paper, the recent developments of intense electromagnetic breakdown at vacuum and air sides of output win- dow and on metal surfaces are reviewed and discussed. To understand the breakdown mechanism at window, several multipactor dynamic models are developed, especially involving electron-neutral collision and ionization in the desorbed gas layer, analytically obtaining the influence of desorption gas on multipactor saturation, and space charge field and potential distribution above dielectric surface formed by multipactor and plasma. By diagnosing the time- and space-evolution optical emissions, the mechanisms of nano-second microwave-driven discharges near the dielec- tric/vacuum and dielectric/air interface were discussed. For breakdown at the dielectric/vacuum interface, multipactor and plasma developing in a thin layer of several millimeters above interface, revealing intense ionization concentrated in a desorbed high-pressure layer. For breakdown at the dielectric/air interface, nonlinear positive feedback of formation of a space-charge microwave sheath near the dielectric surface, accelerated by the normal components of the microwave field, significantly enhances the local-field amplitude and hence ionization near the dielectric surface. The mechanism and methods of using magnetic field satisfying specific amplitude and direction perpendicular to Eqx Edc to suppress microwave multipactor were theoretically studied and experimental demonstrated. The methods of the external resonant magnetic field have been demonstrated by pro

关 键 词：高功率微波 强电磁场击穿 等离子体 输出窗放电 大气放电 金属放电 

分 类 号：O461[理学—电子物理学] O53[理学—物理]