斜向通道雷电电磁场远场近似特性  

Approximate characteristics of far-field lightning electromagnetic field from oblique discharge channel

作　　者：王晓嘉[1] 陈亚洲[1] 万浩江[1] 王琳[1] 

机构地区：[1]军械工程学院静电与电磁防护研究所,石家庄050003

出　　处：《强激光与粒子束》2013年第3期699-703,共5页High Power Laser and Particle Beams

基　　金：国家自然科学基金项目(51077132)

摘　　要：为了使雷电电磁场的计算更加接近实际情况,并对远场区雷电电磁脉冲场进行模拟,利用偶极子理论对斜向放电通道雷电电磁场解析表达式进行了求解,用解析方法对地表雷电电磁场及其导数在远场区的一阶、二阶近似表达式进行了推导,得到了电磁场及其导数与通道底部电流及其导数的远场近似关系。采用脉冲函数表示通道基电流,对比了精确表达式与近似表达式计算的电磁场及其导数波形。结果表明在远场区,斜向通道雷电电磁场波形与其近似波形的偏差、电磁场导数波形与其近似导数波形之间的偏差均随着距离的增加而减小,且电磁场导数近似公式要比电磁场近似公式适用范围更加广泛。计算结果验证了解析推导近似的可行性。In order to make the calculation of lightning electromagnetic field closer to the actual status and simulate the lightning electromagnetic field in far zone, the analytical expressions of lightning electromagnetic field generated by oblique chan- nel were derived with the dipole method, and the approximate relationships of lightning electromagnetic field and its derivative to channel base current were obtained after approximate treatment of the exact analytical expressions for lightning electromagnetic field in far area. The waveforms of lightning electromagnetic field and its derivative from the exact and approximate results were compared based on the specified channel-base current described by a pulse function. The result shows that the difference between the exact and approximate waveforms decreases with the increase of the distance, and the applicable range for the approximate ex- pressions of lightning electromagnetic field is stricter than that of the electromagnetic field derivative. The above result verifies the credibility of the approximate expressions, and provides the theoretical basis for the simulation of lightning electromagnetic fields in far zone.

关 键 词：雷电回击电磁场 斜向放电通道 偶极子法 特性分析 远场区 回击模型 

分 类 号：P427[天文地球—大气科学及气象学]