空间飞行体远尾区内场和密度的非稳态非线性计算

对空间飞行体远尾区内等离子体与场之间非稳态非线性相互作用的耦合方程,在考虑了时间导数项后,进行了数值模拟计算.计算中考虑到场量具有轴对称的特点,利用二维三分量的初始条件,采用FTCS有限差分格式方法,得到了场和密度扰动的分布.结果表明,这种非线性相互作用也会引起场的塌缩并出现密度空洞,但塌缩的速度较快.通过对密度空洞变化的探测,可以对隐身飞行体进行跟踪探测.

THE NONSTEADY AND NONLINEAR INTERACTION BETWEEN PLASMA WITH THE FIELD IN WAKE REGION OF A MOVING BODY IN SPACE

The interaction between a body in space and its plasma environment is one of the basic problems in space plasma physics. Based on a set of the coupled equations that describe the non-steady and non-linear interactions between plasma and the electromagnetic field in the wake region of a moving body in space, using the method of numerical simulation, the evolutions of the density distributions of charged particles and collapses of electric field are obtained. Considering the property of axial symmetry of field quantity, the initial conditions of two dimensions with three field components and the method of limited differencial, FTCS （time forward-differencial and space central-differencial method）, have been used. The initial condition must satisfy the condition of transverse wave ▽·Ê（ȓ,τ=0）=0 and the basic parameters in numerical calculation are V0 = 106cm/s, Te = 2780 K, ne0 = 1 × 105 cm-3, R0 = 100 cm, Ê0 = 0.15. It is noticeable that we take into account the effect of time derivative on the density disturbance and field distribution, which is not considered in previous researches. The results of numerical calculations show that the density cavitons and potential solitons are formed due to the modulational instability. Comparing with the previous works5]-7], the velocity of the collapse is faster relatively. By detecting the distribution of density catiton, the moving body can be traced out by means of the change of the density caviton, although the body may be a stealth vehicle which can not be detected by the radar.