回击速度对雷电电磁场近似关系的影响  

The Influence of Return-Stroke Speed on the Approximate Relationship of Lightning Electromagnetic Field

作　　者：王李鹏[1] 陈亚洲[1] 万浩江[1] 王晓嘉[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：《微波学报》2017年第1期25-31,共7页Journal of Microwaves

基　　金：国家自然科学基金(51377171)

摘　　要：为了探索雷电回击通道底部电流与回击电磁场之间的关系,基于TL模型在近场区和远场区对雷电电磁场近似表达式进行了推导,在此基础上研究了回击速度对底部电流和雷电电磁场之间近似性的影响。研究结果表明:在近场区电磁场与底部电流之间的差异主要集中在峰值部分,而在远场区二者之间的差异主要集中在峰值过后的下降沿部分,但无论在近场区还是远场区,二者之间的偏差均会随着回击速度的增大而减小,当回击速度接近光速时,二者波形几乎完全重合。在v=c时基于不同的电磁场成分对电磁场与底部电流之间的关系进行了推导,结果显示当v=c时近场近似与远场近似将统一为一个相同的表达式,且此表达式在推导过程中不存在任何近似,进一步证明了当v=c时,无论在近场区还是远场区地表电磁场波形与底部电流波形完全一致。Firstly, the approximate formulas between lightning electromagnetic fields and return-stroke channel base current are derived in field range and far field range in this paper, after that we researched the effect of return-stroke speed on relationship between channel base current and lightning electromagnetic fields in near area and far area, respectively. Re- sult show that, the difference between channel base current and lightning electromagnetic fields in near area is concentrated in the peak portion of waveforms, while the difference between channel base ct/rrent and electromagnetic fields in far field range is focused on the falling edge part of waveforms, but the differences between them are decrease with the increase of return- stroke speed. If the return-stroke speed is equal to speed of light, the approximate equations between channel base current and lightning electromagnetic fields in near area and far area will normalized to unified expressions, which validated that if v = c electric and magnetic field waveforms and channel base current waveform are identical at all point in space.

关 键 词：雷电电磁场 回击速度 回击通道底部电流 近似性 

分 类 号：P427.3[天文地球—大气科学及气象学]