高空极端爆炸缓发辐射电离的数值模拟

Numerical simulation of delayed radiation ionization from high-altitude extreme explosions

  • 摘要: 高空极端爆炸缓发辐射电离效应的评估涉及爆炸碎片云的时空演化、辐射输运及大气电离等复杂物理过程。针对传统经验模型适用范围有限、蒙特卡罗输运计算代价较高等问题,本文提出一种融合深度学习与标准辐射传输理论的缓发辐射电离效应评估方法。首先,采用深度学习方法构建数据驱动的碎片云时空演化模型,用以表征碎片云面源或体源的空间分布特征;随后,结合标准辐射传输理论、大气衰减吸收机制及解析-半经验公式,建立缓发γ射线和β粒子输运电离计算模型,获得缓发辐射电子生成率的空间分布。研究结果表明:碎片云的空间分布显著影响缓发辐射的电离范围与强度,随着碎片云高度和半径的增加,电离区域随之扩大,电子产生率的峰值有所降低;缓发γ射线电离范围较广,最大半径超过3 000 km;而β粒子受地球磁场束缚影响,电离范围相对较小,但局部电离强度要比γ射线高出约一个数量级。

     

    Abstract:
    Background The numerical assessment of delayed radiation ionization from high-altitude extreme explosions involves complex processes, including debris evolution (as surface or volume sources), radiation transport, and atmospheric ionization. Traditional empirical formulas have limited applicability under certain high-altitude conditions, while Monte Carlo methods are inefficient for hour-scale simulations.
    Purpose This study aims to develop an efficient assessment method by constructing a data-driven debris-cloud model using deep learning and coupling it with standard radiation transport theory and atmospheric attenuation mechanisms, so as to calculate the spatial distribution of the delayed-radiation-induced electron production rate.
    Methods The debris model was developed using deep learning techniques. Then, an analytical-semi-empirical assessment model was developed by combining radiation transport theory and atmospheric attenuation mechanisms. This model was used to compute the spatial distribution of the electron production rate under high-altitude explosion conditions.
    Results The results indicate that the spatial distribution of debris significantly affects the ionization range and intensity. As the debris height and radius increase, the ionization area expands, but the peak electron production rate decreases. Delayed γ-rays exhibit a wide ionization range, with a maximum radius exceeding 3,000 km. In contrast, β-particles have a limited range due to geomagnetic confinement, yet their local ionization intensity is one order of magnitude higher than that of γ-rays.
    Conclusions The proposed deep learning-based debris model combined with the analytical-semi-empirical approach provides an efficient and accurate alternative to traditional empirical formulas and computationally intensive Monte Carlo methods. This method effectively captures the key impacts of debris geometry and radiation type, offering a practical tool for assessing delayed radiation ionization from high-altitude extreme explosions over extended time scales.

     

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