Numerical and experimental studies on the effectiveness of time-varying electromagnetic fields in reducing electron density  

作　　者：郭韶帅 谢楷 徐晗 付麦霞 牛营营 Shaoshuai GUO;Kai XIE;Han XU;Maixia FU;Yingying NIU(Key Laboratory of Grain Information Processing and Control(Henan University of Technology),Ministry of Education,Zhengzhou 450001,People's Republic of China;College of Information Science and Engineering,Henan University of Technology,Zhengzhou 450001,People's Republic of China;School of Aerospace Science and Technology,Xidian University,Xi'an 710071,People's Republic of China)

机构地区：[1]Key Laboratory of Grain Information Processing and Control(Henan University of Technology),Ministry of Education,Zhengzhou 450001,People's Republic of China [2]College of Information Science and Engineering,Henan University of Technology,Zhengzhou 450001,People's Republic of China [3]School of Aerospace Science and Technology,Xidian University,Xi'an 710071,People's Republic of China

出　　处：《Plasma Science and Technology》2023年第6期30-40,共11页等离子体科学和技术（英文版）

基　　金：supported by the Research Foundation for Advanced Talents of Henan University of Technology(No.31401482);National Natural Science Foundation of China(No.52107162);the Research Foundation for University Key Teacher of Henan Province(No.2020GGJS084);the Research Foundation for Key Teacher of Henan University of Technology;the Foundation of Henan Science and Technology Agency(No.222102210186)。

摘　　要：When an aircraft or a hypersonic vehicle re-enters the atmosphere,the plasma sheath generated can severely attenuate electromagnetic wave signals,causing the problem of communication blackout.A new method based on time-varying E×B fields is proposed to improve on the existing static E×B fields and mitigate the radio blackout problem.The use of the existing method is limited by the invalid electron density reduction resulting from current density j=0 A m^(-2)in plasma beyond the Debye radius.The most remarkable feature is the introduction of a time-varying electric field to increase the current density in the plasma to overcome the Debye shielding effect on static electric field.Meanwhile,a magnetic field with the same frequency and phase as the electric field is applied to ensure that the electromagnetic force is always acting on the plasma in one direction.In order to investigate the effect of time-varying E×B fields on the plasma electron density distribution,two directions of voltage application are considered in numerical simulation.The simulation results indicate that different voltage application methods generate electromagnetic forces in different directions in the plasma,resulting in repulsion and vortex effects in the plasma.A comparison of the vortex effect and repulsion effect reveals that the vortex effect is better at reducing the electron density.The local plasma electron density can be reduced by more than 80%through the vortex effect,and the dimensions of the area of reduced electron density reach approximately 6 cm×4 cm,meeting the requirements of electromagnetic wave propagation.Besides,the vortex effect of reducing the electron density in RAM-C(radio attenuation measurements for the study of communication blackout)reentry at an altitude of 40 km is analyzed.On the basis of the simulation results,an experiment based on a rectangular-window discharge device is proposed to demonstrate the effectiveness of the vortex effect.Experimental results show that time-varying E×B fields can reduce the

关 键 词：BLACKOUT magnetic window method time-varying E×B fields 

分 类 号：V216.5[航空宇航科学与技术—航空宇航推进理论与工程] O441.4[理学—电磁学]