三维雷暴云电耦合数值模式中空间电位的求解

Solution of the Space Potential in a Three-Dimensional Dynamic-Electrification Coupled Model

将电路分析方法引入三维雷暴云动力—电耦合数值模式中,考虑了带电水成物粒子对电导率的影响,直接用模式计算求解与雷暴云中流动的带电粒子有关的电流密度。比较分析了雷暴云内首次放电出现之前电路分析法和泊松方程得到的电位和电场。结果表明,雷暴云内电导率普遍大于晴天大气,峰值位于各极性电荷区中心。与雷暴云中流动的带电粒子有关的电流密度的正、负最大值分别对应正、负电荷区中心,当电荷密度的绝对值不超过0.7nC.m-3时,其最大值的量级为10-9A.m-2,传导电流和位移电流最大值的量级均为10-8A.m-2,都为负,均在中部负电荷区中心。电路分析法得到的电位的垂直廓线与电荷结构的相互关系更明显,垂直电场的正、负最大值分别处于电荷密度最大的中部负电荷中心的上边缘和下边缘,与以往的观测结果更接近。

The electronic circuit analysis is used in a three-dimensional dynamic- electrification coupled model, and the effect of hydrometeors with charge to conductivity and current density are included in this paper. The electric potentials and fields before the first discharge presenting are resolved by Poisson equation and electronic circuit analysis, respectively. The results indicate that the conductivity in thundercloud is greater than in fair weather, and peaks correspond with the centers of charge regions. The positive and negative maxima of current density that associated with charged particles circulating correspond with the centers of positive and negative charge regions, respectively. When the charge density is less then 0.7nC ·m-3 , the magnitude of the maxima of current density that associated with charged particles circulating is 10-9A·m-2 , and conduction current density and displacement current density are 10-8A·m-2. The re- lationship between the vertical profile of electric potential and charge structure is obvious by the electronic circuit analysis. The positive and negative maxima of vertical electric field are located in the upper and lower edge of main negative charge region, respectively. This is close to the observational results.