Research Of Related Physical Mechanism Of Ultraviolet Radiation In Missile Plume

In the modern information war, missile occupies a pivotal position. Therefore, how to defense the missile has become an important research subject in the military. Among all the missile warning technologies, the technology based on the ultraviolet (UV) radiation in missile plume is drawing increasing attention. As a consequence, the related physical mechanism of ultraviolet radiation from missile plume becomes a key issue of UV warning technology.In this paper, two main UV radiation sources of missile plume---hot particle radiation and chemiluminescence are studied. Numerous hot alumina particles will be generated during the combustion process of missile propellant, thus cause a strong UV radiation. For alumina particles in three different phases, the crystal structure and complex refractive index are analyzed, and then the corresponding radiation characteristics are calculated. Taking the phase transition into account, a dynamic radiation model of liquid alumina particle during solidification process is built.Chemiluminescence is also one of UV radiation causes in missile plume, and is mainly resulted from the recombination of carbon monoxide and oxygen molecule in the solar-blind band. Due to the close relation between chemiluminescence mechanism and molecular level properties, this paper analyzes the potential energy curves and spectroscopic constants of carbon monoxide on the ground state and low-lying electronic states, and also calculates the transition dipole moment during specific transition process.Based on the analysis of two main physical mechanisms of UV radiation in missile plume, a model of UV radiation in missile plume is established. The missile plume is abstracted into a cylinder, and the internal non-gray media is assumed to be axisymmetric. Under cylindrical coordinate system, the differential form of radiative transfer equation is transformed into discrete one by finite volume method, to obtain the radiation characteristics of missile plume.Finally, the UV transmission law in the atmosphere is studied. The single scattering UV transmission model is built based on the ellipsoidal coordinates, to analyze the impact of geometric structure on path loss. Then, this paper uses Monte Carlo method to establish the multiple scattering UV transmission model. By simulating the behavior of photon transmission in the atmosphere, the statistical laws of UV transmission are obtained. Moreover, atmospheric stratification in atmosphere that is non-uniform in vertical direction is also carried out. As a result, each layer is approximately uniform after stratification, and ultimately the multiple scattering model of UV transmission is established in non-uniform atmosphere.