结合MCNP的自恰近地面源区电磁脉冲数值模拟方法

Self-Consistent Numerical Simulation Method of Near Ground Source Region Electromagnetic Pulse Combined With MCNP

利用MCNP程序模拟了近地面核爆炸时地面附近的射线辐射环境,考虑了大地和空气对射线的散射作用和对中子的俘获作用,更加符合真实情况。在圆柱坐标系下,基于电流模型编写了考虑场-束自恰作用的2维源区电磁脉冲(source region electromagnetic pulse,SREMP)数值模拟程序,对MCNP的计算结果进行插值处理,为电磁脉冲模拟程序计算电流源和电导率提供输入信息。模拟结果表明,在源区电磁脉冲的计算中,电磁场对电流的修正作用不可忽视。对某一特定辐射情况下的源区电场环境进行了计算,计算结果表明,在一定区域内,SREMP可产生幅值高于高空核电磁脉冲的电场强度,且二者频率分布不同,需进行针对性的防护加固。

In this paper,MCNP is used to simulate the ray radiation environment above the ground during the near ground nuclear explosion.The following results accord better with the real nuclear burst condition because the scattering effect on rays and the capture effect on neutrons induced by the ground and air are considered.In the cylindrical coordinate system,a 2D source region electromagnetic pulse(SREMP)numerical simulation code considering the self-consistent wave-beam effect is developed based on the current model.The computational results of MCNP are interpolated to provide input information for the calculation of power supply current source and conductivity in the electromagnetic pulse simulation code.The simulation results show that the correction effect of electromagnetic field on current cannot be ignored in the calculation of source region electromagnetic pulse.The electric field environment in the source region under a specific radiation condition is calculated.The results show that in a certain region,SREMP can produce an electric field intensity with an amplitude higher than that of high-altitude nuclear explosion,and the frequency distributions are different,which requires protection-hardened.