从空间飞行器注入电离层的调制电子束产生的电磁波辐射

Electromagnetic wave excitation by a modulated electron beam injected from spacecraft into the ionosphere

调制电子束入射进电离层等离子体中会激发电磁波辐射,根据不同试验条件和等离子体状态,激发电磁波的机制也不一样.本文主要讨论半无界稀薄调制电子束沿地球磁场力线从空间飞行器入射到电离层等离子体产生的电磁波辐射,其相应的辐射机理是由于束的纵向约束而产生的电磁波辐射.理论分析和数值计算结果显示,在满足切伦柯夫(Cerenkov)共振条件时,哨声波前向辐射方向图有一个尖锐的峰值,且随着电子束弛豫长度的增加,辐射功率值也相应增大,表明可以通过对电子束的适当调制增强电子束激发的电磁波辐射强度.

Electromagnetic wave excitation can be excited by injecting modulated electron beam into ionosphere, by varied mechanisms under different experimental conditions. This article presents the calculation of the radioemission of a semi-restricted thin modulated electron beam injected from the spacecraft board into the ionosphere plasma along the geomagnetic field. The result shows that the radiation pattern for whistlers＇ frequency range has a sharp maximum that corresponds to the Cherenkov resonance condition. The intensity of electromagnetic wave can be strengthened by electron beam modulation.