地-电离层中水平激发极低频场的勒让德展开算法  

Legendre function series method for ELF fields excited by horizontal electric dipole in earth-ionosphere cavity

作　　者：彭怀云[1] 潘威炎[2] 郭立新[1] 

机构地区：[1]西安电子科技大学理学院,陕西西安710071 [2]中国电波传播研究所,山东青岛266071

出　　处：《电波科学学报》2013年第5期851-856,876,共7页Chinese Journal of Radio Science

摘　　要：地-电离层空腔中水平激励极低频(Extremely Low Frequency,ELF)场强可表示为勒让德函数及其导数的级数和,利用勒让德函数迭代公式,提出了极低频水平偶极子在地-电离层空腔中激励场的计算新算法.将该方法近区场的计算结果与半空间水平偶极子激励场计算结果对比,远场区结果与Bannister(dir.+ind.)公式计算结果对比,验证了新算法的正确性和精度.将本算法应用至几Hz以下,可获得特殊规律:远区电场、磁场水平分量与方位角无关,电场水平分量方向与偶极矩方向平行,磁场水平分量方向与之垂直.Extremely low frequency （ELF） propagation formulas for horizontal e- lectric dipole sources radiating in a spherical uniform earth-ionosphere cavity have a range dependence characterized by either the Legendre function of the first kind of complex degree v and order zero or one of its first two derivatives. Using the itera- tire formulas of Legendre function, A new method is presented in this paper. The resulting waves are expressed as a superposition of T M and T E modes. In the near-filed range, the method of images is expected to be similar to the near fields of a dipole located on a flat finitely conducting, the far field is same as the result of Bannister（dir. ＋ind. ） formulas. This shows that the method is accurate. The re- sult of frequencies under 1 Hz show that the horizontal electric and magnetic com- ponents are independent of the azimuth ~, and the direction of horizontal electric components is parallel to the dipole axis in the isolines chart with distance, where- as, the direction of horizontal magnetic components is orthogonal to dipole axis.

关 键 词：极低频 地-电离层空腔 水平偶极子 电场水平分量 磁场水平分量 

分 类 号：P352[天文地球—空间物理学]