空间飞行器远尾区内等离子体与场的相互作用

【作者】 胡涛平；

【导师】 李晓卿；

【作者基本信息】 南京师范大学 ， 天体物理， 2003， 硕士

【摘要】 本文主要研究了飞行器在电离层中运动时，与周围的等离子体之间发生的非线性、非稳态相互作用问题。这种相互作用对飞行器的影响，一方面是带电粒子的密度会发生变化；另一方面则是由于带电粒子的密度变化而引起飞行器周围区域电场的变化。全文共分四章对此问题进行研究。 第一章主要是介绍了有关空间等离子体物理过程中的一些基本概念，讨论了一些普遍的相互作用机制。并给出了在研究飞行器与周围的等离子体之间发生相互作用时，基本的空间环境参量，采用的基本方程，等离子体的一些不稳定性以及最近的一些研究情况。 第二章是从描述电子的磁流体方程和麦克斯韦方程出发，通过计算，最后得到了一组在考虑非静态极限下描述空间飞行器远尾区内等离子体与场之间的非稳态非线性相互作用耦合方程。 第三章是在给定一个初始的扰动横场条件下，并选取好所需要的电离参数，然后对已求得的这组方程进行数值模拟。数值计算结果表明，由于飞行器与周围的等离子体之间发生相互作用，电场会产生塌缩现象，形成电磁孤波；电子密度则产生密度空腔。 第四章我们给出了一些主要结论，阐明了所形成的电磁孤波和密度空腔的一些特性。这些对研究隐身飞行器的探测问题，具有很重要的意义。更多还原

【Abstract】 In this thesis, the non-steady and nonlinear interactions between the aircraft and space plasma have been studied in detail when the aircraft moves in ionosphere. The influence of these interactions lie in two aspects: on one hand, the concentration of charged particles will change; on the other hand, the alteration of electric field can also appear because of the change of the distribution of charged particles around the aircraft. To investigate these problems, the thesis consists of four chapters.In chapter one, some basic concepts about plasma physics and some general mechanisms of interactions have been introduced. In addition, we also introduce the parameters of space environment, basic equations which usually are used, some instabilities of plasma and some results of research when we discuss these problems of interactions between the aircraft and space plasma around it.In chapter two, using the hydrodynamical equations for electrons and Maxwell equation and through complicated calculation, we finally obtain a set of equations which describe the non-steady and nonlinear interactions between plasma and field in the wake region of a moving body in space.In chapter three, giving an initial disturbed transverse electric field and selecting the parameters in ionosphere, then we numerically simulate these equations we have get. The results of numerical calculation show that the electric field will collapse then produce solitons and density cavitons are formed due to the interactions between the aircraft and plasma.In chapter four, some discussions and conclusions are presented. And we also elucidate some characteristics of solitons and density cavitons which have formed, which has most important value to detect the moving body which has a ’stealth’ characteristic.更多还原