等离子体是广泛存在于自然界中的一种电中性的电离气体,是继物质存在的固体、液体、气体三种形态之后出现的第四种物质形态,具有数密度近似相等的自由电子和正离子,其产生和运动主要受电磁场力的作用与支配,对电磁波的传播有很大的影响。自20世纪60年代以来,美国和苏联等军事强 Plasma is a kind of electrically neutral ionized gas which is widely found in nature. It is the fourth material form that appears after the three forms of matter, such as solid, liquid and gas, and has the similar number density of free electrons and positive ions Its generation and movement are mainly influenced and controlled by the electromagnetic force, which has a great influence on the propagation of electromagnetic waves. Since the 1960s, the United States and the Soviet Union have maintained their military strength