【摘要】 在主动束-等离子体试验中,调制电子束从空间飞行器入射进电离层等离子体将会产生电磁波辐射, 在不同试验条件下电磁波辐射机理也不一样,由电子束纵向约束性产生电磁波辐射是其中之一,对半无界稀薄调制电子束从空间飞行器入射进电离层等离子体时所产生的波现象进行了理论分析和数值计算,结果表明, 当调制电子柬沿磁力线入射时,会在电离层等离子体中产生高频电磁波辐射,该辐射主要集中在垂直于入射电子束运动方向的平面内。更多还原

【Abstract】 Waves excitation in the ionosphere by the modulated electron beams was observed in some active plasma experiments in space. In the active beam-plasma experiments electromagnetic wave can be excited by injecting modulated electron beam into the ionosphere, by various mechanisms according to different experimental conditions. The frequency of this sort of radioemission is determined by the beam modulation; it can lie in the whistler band or in the high frequency band (higher than electron plasma frequency). This article gives a theoretical analysis as well as quantitative calculation of the radioemission of semi-restricted thin modulated electron beam injected from the spacecraft into the ionosphere plasma along the geomagnetic field. The result shows that when the modulated electron beams are injected along the magnetic field line, they can produce high-frequency electromagnetic radiations in the ionosphere plasma. This electromagnetic radiation is mainly observed in the plane that is perpendicular to the velocity direction of the injected electron beam. Estimations show that the radiated power is high enough to be detected.更多还原