等离子体中电磁波传输特性理论与实验研究

本文对35 GHz和96 GHz电磁波在等离子体中的传输特性进行了理论与实验研究, 得到了电磁波衰减随等离子体密度、碰撞频率和电磁波频率的变化规律. 等离子体密度增加一个数量级时, 电磁波衰减增加一个数量级; 随着等离子体碰撞频率的增加, 电磁波衰减先增加后减小; 随着电磁波频率的增加, 衰减下降. 以激波管为实验平台进行了电磁波在等离子体中传输特性的实验研究, 实验结果和理论结果吻合较好. 理论和实验结果均表明, 提高电磁波频率是解决黑障问题的有效途径.

Theoretical and experimental studies of electromagnetic wave transmission in plasma

The aircrafts, such as space shuttle, spaceship and so on, are facing the well-known "blackout" problem when they reentry into the atmosphere. The plasma sheath leads electromagnetic waves to attenuation, and the communications between the aircrafts and the ground to losing, and even completely interrupte, thereby resulting in the loss of radar targets and threatening the lives of the astronauts. Therefore, it is important to study the properties of the electromagnetic wave transmission in plasma. The characteristics of electromagnetic wave transmission in plasma are studied theoretically and experimentally in this paper. The variations of the electromagnetic wave attenuation with plasma density, collision frequency and electromagnetic wave frequency are obtained. The electromagnetic wave attenuation increasean an order of magnitude with plasma density increasing an order of magnitude. The electromagnetic wave attenuation first increases and then decreases with plasma collision frequency increasing, the electromagnetic wave attenuation decreases with the increase of electromagnetic wave frequency. The electromagnetic wave transmission properties in plasma are studied experimentally with shock tube, and the experimental results accord well with the theoretical results. The results show that increasing the electromagnetic wave frequency is an effective way to solve the reentry blackout problem.