地表近场LEMP与回击电流的近似性

由于闪电近区电磁场的瞬时性和高强度的特点,致使其不易测试,其波形也难以捕捉。为了对闪电近场电磁波进行模拟,从理论上对雷电电磁脉冲(LEMP)的地表近区波形和回击通道底部电流的波形进行了探索。用解析方法近似推导近区LEMP的表达式得出,近区LEMP波形与回击通道底部电流波形近似;用偶极子法精确计算近区LEMP的结果表明,在100 m以内磁场波形与近似计算结果基本吻合,在50 m以内,电场波形与近似计算结果基本吻合。计算结果验证了解析推导近似的可行性,证明<50 m的地表近区,LEMP场波形与回击通道底部电流波形相似。这为闪电地表近场电磁波的模拟提供了理论依据。

Characteristic of Approximation Between LEMP in Near Area and Channel base Current.

To simulate the lightning electromagnatic pulse(LEMP) wave in the near field,the LEMP and the lightning return stroke channel base current are theoretically researched.According to the approximation of the expression of LEMP,the waveform of LEMP in near field is similar to the lightning return stroke channel base current.The actual results of LEMP are calculated by the dipole method.According to the results,the magnetic field waveform is closer to channel base current waveform than electric field waveform.But within 50m both the electric field waveform and the magnetic field waveform are close to the channel base current waveform.The comparison of approximate results and calculated results shows that the approximation between the waveform of LEMP in near field of lightning return stroke channel and the waveform of lightning channel base current is believable.