薄层感性耦合等离子体参数非均匀性对电磁散射特性的影响研究

Plasma stealth technology has the potential to deal with ultra-wideband anti-stealth detection. The thin-layer inductively coupled plasma (ICP) has outstanding advantages in plasma stealth, including the coverage of Ka-band, the suitable geometry for radar scattering sites, and the large discharge area. However, the strong radio-frequency electric field and other factors in the thin-layer ICP source influence the coefficients of electron transport/diffusion, resulting in a significant increase in the non-uniformity of the parameter distribution, and a series of scattering effects in the electromagnetic wave propagation. In addition, there are significant spatial differences in the scattering characteristics. Due to the lack of understanding of the parameters distribution and space-time characteristics of scattering effects, the spatial electromagnetic scattering characteristics cannot be analyzed. In this project, the influence mechanism of parameters non-uniformity distribution on the spatio-temporal evolution of scattering characteristics is the research core. By constructing a high-pressure ICP source discharge model in a thin layer dielectric cavity and carrying out verification tests, a parameter distribution model is obtained to explore the key factors and influenced mechanism of dominant parameter non-uniformity. Through the construction of space-time coupling model of ICP-electromagnetic wave propagation, the spatio-temporal characteristics of scattering effect and the spatial scattering parameter model are obtained. The space-time evolution mechanism of scattering effect is revealed, and the spatial difference of near-far field scattering characteristics is obtained. The project results provide a theoretical basis and technical support for solving the optimization of thin-layer ICP source structure and enhancing the effect of absorbing waves.

等离子体隐身技术应对超宽带反隐身探测更具潜力，薄层感性耦合等离子体（ICP）响应频带覆盖Ka波段、几何结构适用于雷达散射部位、放电面积大，在等离子体隐身方向应用优势突出。薄层ICP源中存在的强射频电场等因素改变电子输运/扩散等系数，导致参数分布的非均匀性大幅提升，并引起电磁波传播中一系列散射效应，进而散射特性出现显著空间差异，由于缺乏对参数分布规律和散射效应时空特性的认识，导致无法分析其空间电磁散射特性。本项目以研究参数分布对散射效应时空演化的影响机理为核心，通过构建薄层介质腔中高气压ICP源放电模型并开展验证试验，获得参数分布模型，探究主导参数非均匀性的关键因素和影响机理；通过构建ICP-电磁波传播时空耦合模型，获得散射效应时空特性和空间散射参量模型，揭示散射效应的时空演化机理，获得近远场散射特性的空间差异规律。项目成果为解决薄层ICP源构型优化、吸波效果提升提供理论基础和技术支撑。

薄层透波腔射频感性等离子体（ICP）源具有电子密度高、调控手段多样等优点，通过调控其参数分布可实现对电磁波反射特性的调控，在动态等离子体隐身和反射面天线领域具有较高应用潜力。本项目系统地研究薄层透波腔感性耦合等离子体放电特性，揭示了特征参数非均匀分布的关键影响因素和影响机理，建立了玻尔兹曼方程修正流体力学模型，在宽放电条件和多时间尺度上获取等离子体参数分布，实验和仿真结果表明，薄层、介质腔、中高气压感性放电主等离子体区存在的强射频电场、碰撞效应、高电位因素，导致参数分布的非均匀性大幅提升，带电粒子的能量分布、电离和输运扩散过程决定了参数的最终分布，分析了不同放电进程中参数分布的空间演化过程，获得参数分布模型，探究主导参数分布非均匀性的关键因素和影响规律。.建立了电磁波在感性耦合等离子体中传播和散射时空演化模型，获得了参数非均匀分布下散射效应时空演化机理，薄层 ICP 参数分布的非均匀性显著增强，电磁波传播中除了衰减和相移外，出现多重散射和入射波聚散焦效应，在等离子体的密度中心区域形成假源（点波源）、反射波不再以平面波形式传播，分析参数非均匀分布与散射效应时空特性之间的耦合关系，获得了参数分布对吸波特性的影响。研究成果对深化薄层ICP 参数分布调控机理、推进等离子体隐身和反射面天线的工程应用具有重要意义，为解决超宽带动态等离子体隐身技术、多频段等离子体反射面天线中等离子体源设计和微波反射特性动态调控提供理论基础和关键技术支撑。