基于碎片云运动模型的缓发γ射线电离大气蒙特卡罗模拟

he delayed -rays released from the debris of a high-altitude nuclear explosion ionize the atmosphere during transport in the high-altitude non-uniform atmosphere, causing a dramatic increase of the electron number density in the ionosphere, which affects the radio communication links through the ionosphere. In order to accurately describe the delayed -ray sources which evolves in time and space, we firstly establish a hydrodynamic model of the evolution of debris motion of a high-altitude nuclear explosion, then establish a hierarchical equivalent model of delayed -ray sources according to the debris parameters, and finally apply the Monte Carlo method to simulate the ionization effect of the delayed -rays in the high-altitude non-uniform atmosphere. Because the debris shape continuously evolves with time, a method of stratified sampling of the radiation source is built to obtained the initial positions of the delayed -rays. Due to the atmosphere density decaying exponentially with height, the mass thickness sampling method is used to simplify the calculation model. The results show that the ionization intensity and range of delayed -rays are significant influenced by the shape of the debris. The ionization range of delayed -rays in a megaton level high-altitude nuclear explosion can reach more than a thousand kilometers. When the equivalent increases with a constant explosion height, the debris height and horizontal radius increases, the ionization range and intensity of the atmosphere caused by the delayed -rays increase. When the burst height increases with a constant equivalent, the debris height and horizontal radius increases, the ionization range caused by the delayed -rays increases, while the ionization intensity decreases.