时变等离子体与电磁波相互作用研究
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摘要
通过实验验证了时变等离子体对电磁波产生的调制,证明了该调制的频率与等离子体变化频率保持一致,该调制本质是因为电磁波进入等离子体后波矢发生了改变,导致电磁波的幅度和相位产生了变化等离子体类似色散介质。随着信号的频率上升,等离子体调制的强度减弱。对调制后的信号进行解调幅和解调相,验证了调幅信号和调相信号具有同周期,但是周期内的变化不一样。
Through experiments, this paper validates the modulation on electromagnetic waves generated by time variation plasmas, and proves that the frequency of the modulation keeps consistent with the variation frequency of the plasmas. The essence of this modulation is because the wave vector changes after the electromagnetic waves enter the plasmas, which induces the changes on phases and amplitudes of the electromagnetic waves, and at this time, the plasma is similar to a dispersive medium. The influences of plasmas modulation weakens with the signal frequency increasing. After the demodulation of the amplitude and the phase of the modulated signals, it verifies that the amplitude modulation signals and the phase modulation signals have the same period, but vary differently in the period.
Through experiments, this paper validates the modulation on electromagnetic waves generated by time variation plasmas, and proves that the frequency of the modulation keeps consistent with the variation frequency of the plasmas. The essence of this modulation is because the wave vector changes after the electromagnetic waves enter the plasmas, which induces the changes on phases and amplitudes of the electromagnetic waves, and at this time, the plasma is similar to a dispersive medium. The influences of plasmas modulation weakens with the signal frequency increasing. After the demodulation of the amplitude and the phase of the modulated signals, it verifies that the amplitude modulation signals and the phase modulation signals have the same period, but vary differently in the period.
引文
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[8] 杨敏,李小平,刘彦明,等.信号在时变等离子体中的传播特性[J].物理学报,2014,63(8):085201.YANG Min,LI Xiaoping,LIU Yanming,et al.Propagation of electromagnetic signals in the time-varying plasma[J].Acta Physica Sinica.2014,63(8):085201.
[9] NAKANO Y,KOJIMA H,HAYAKAWA N,et al.Predischarge and flashover characteristics of impulse surface discharge in vacuum[J].IEEE Transactions on Dielectrics & Electrical Insulation,2014,21(1):403-410.
[10] KOJIMA H,ISHIDA M,HAYAKAWA N,et al.Partial discharge characteristics and mechanisms in consideration of charge behavior on alumina dielectrics under AC voltage in vacuum[J].International Conference on Electric Power Equipment,2013,10(2):20-23.
[11] NAKANO Y,KOJIMA H,HAYAKAWA N,et al.Development process of impulse surface discharge in vacuum[C]// Proceedings-International Symposium on Discharges and Electrical Insulation in Vacuum.ISDEIV:[s.n],2012:125-128.
[2] HARTUNIAN R A,STEWART G E,RAVN O.Causes and mitigation of radio frequency blackout during reentry of reusable launch vehicles[R].El Segundo:Aerosp.Corporation,2007.
[3] POTTER D L.Introduction of the PIRATE program for parametric reentry vehicle plasma effects studies[C]// The 37th AIAA Plasma Dynamics and Lasers Conference.San Francisco,USA:[s.n],2006:5-8.
[4] DANIEL G,JOSEPH S,ROBERT S.Electromagnetic wave propagation in unmagnetized plasmas[R].Malibu,CA:Hughes Research Laboratories,1992.
[5] HEALD M A,WHARTON C B.Plasma diagnostics with microwaves[M].Hungtington,New York:Robert E.Krieger Publishing Company,1978.
[6] LIN T C,SPROUL L K.Influence of reentry turbulent plasma fluctuation on EM wave propagation[J].Computers Fluids,2006,35:703-711.
[7] OHLER S G,GILCHRIST A D,GALLIMORE A D.Electromagnetic signal modification in a localized high-speed plasma flow:simulations and experimental validation of a stationary plasma thruster[J].IEEE Transactions Plasma Science,1999,27(2):587-594.
[8] 杨敏,李小平,刘彦明,等.信号在时变等离子体中的传播特性[J].物理学报,2014,63(8):085201.YANG Min,LI Xiaoping,LIU Yanming,et al.Propagation of electromagnetic signals in the time-varying plasma[J].Acta Physica Sinica.2014,63(8):085201.
[9] NAKANO Y,KOJIMA H,HAYAKAWA N,et al.Predischarge and flashover characteristics of impulse surface discharge in vacuum[J].IEEE Transactions on Dielectrics & Electrical Insulation,2014,21(1):403-410.
[10] KOJIMA H,ISHIDA M,HAYAKAWA N,et al.Partial discharge characteristics and mechanisms in consideration of charge behavior on alumina dielectrics under AC voltage in vacuum[J].International Conference on Electric Power Equipment,2013,10(2):20-23.
[11] NAKANO Y,KOJIMA H,HAYAKAWA N,et al.Development process of impulse surface discharge in vacuum[C]// Proceedings-International Symposium on Discharges and Electrical Insulation in Vacuum.ISDEIV:[s.n],2012:125-128.