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讲准字238号:Progress on the Interaction Mechanism of Electromagnetic Waves with Plasma Sheath and EM Sca

亚游官网登录:2016-10-25|浏览次数:

题目:Progress on the Interaction Mechanism of Electromagnetic Waves with Plasma Sheath and EM Scattering/Propagation of Hypersonic Aircrafts in the Near-Space

主讲:郭立新

时间:10月29日13:30

地点:会议中心第二报告厅

主办:计算机科学与通信工程学院


 

主讲概况:郭立新,博士生导师,西安电子科技大学物理与光电工程学院院长,教育部“长江学者奖励计划”特聘教授,国家杰出青年科学基金获得者,入选国家“百千万人才工程”并被授予“有突出贡献中青年专家”荣誉称号,享受国务院政府特殊津贴。教育部首届“青年教师奖”和第六届“中国青年科技创新优秀奖”获得者。现为陕西省无线电物理重点学科带头人,复杂地物环境电波传播与散射“陕西省重点科技创新团队”首席,陕西省教学名师。兼任装发部某预研专业组成员、陕西省物理学会副理事长,中国电子学会会士,教育部科技委学部委员,IEEE高级会员,中国电子学会电波传播分会委员等职。主要从事雷达目标和地海杂波电波传播与散射,目标与粗糙地海面复合电磁散射建模与应用及计算电磁学研究。主持国家973、国家863课题、国家自然科学基金(杰青、重点、面上、青年)、国家科技重大专项、国防科技预研、留学回国人员基金等项目40余项。获国家科技进步三等奖1项,省部级科技进步一等奖1项,二等奖4项;出版学术专著4部,在IEEE Trans. GRS、IEEE Trans. AP、Optics Express和中国科学等国内外刊物发表论文320余篇。

主讲内容:The electromagnetic characteristic of plasma sheath, the interaction between the electromagnetic wave and plasma sheath, as well as the electromagnetic scattering mechanism of a combined plasma sheath and hypersonic aerocraft are examined. Regarding to the key scientific problem of EM wave propagation in the time-varying plasma sheath, this talk presents an electromagnetic wave propagation and scattering models for plasma sheath of hypersonic aerocraft in the near space. The propagation properties of electromagnetic wave in a moving non-uniform plasma are introduced in this work. By utilizing WKB approximation method, the non-uniform plasma density of a parabolic profile is taken as an example to make analyses about propagation behavior. To further explore the effects of spreading in the plasma sheath on the electromagnetic wave, the modified JE convolution-finite-difference time-domain and physical optics (PO) method algorithm are applied to three-dimensional inhomogeneous and time-varying plasma. The radar cross-section (RCS) and attenuation of plasma sheath are simulated and analyzed with different temperature, collision frequency, and electron density varying with time. In addition, a new fractal model and power spectrum of plasma sheath turbulence are established based on the fractal dimensions in hypersonic turbulence which are measured through experiments. The expression for beam spot size, scintillation index, angle-of-arrival fluctuation, and beam wander are obtained from the power spectrum. The propagation characteristics of a Gaussian beam in a turbulent plasma sheath are discussed. Numerical results show that plasma sheath turbulence will lead to amplitude and phase variations.


 

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