摘要
研究带电粒子对电磁波的散射,对认识电磁场规律及云层探测、雷电预警等具有重要意义;根据带电粒子的米氏散射理论,对散射系数进行简化,得到了带电粒子在瑞利散射条件下,散射系数与面电导率和电磁阻抗系数的关系;计算了瑞利散射条件下,不同面电导率的粒子的电磁波散射系数,在粒子尺度较小时,瑞利散射公式与米氏散射公式计算结果一致。粒子表面所带电荷改变了面电导率,当面电荷使面电导率达到毫西门子量级时,就会使散射系数有明显增加,随着面电导率的增加,散射系数会有较大变化;对尺度系数较小的粒子,散射系数较小,但带电后散射系数与中性时的散射系数之比较大,并随着电导率的增加趋于一个恒定值,大小与粒子的介电系数有关,对球形水滴这一恒定值约为24。
Research of the scattering of electromagnetic waves by charged particles is significant for the thorough understanding of electromagnetic field and the detection of the clouds and lightning warning.According to the theory of the Mie scattering of the charged particles and the characteristics of the Rayleigh scattering, the simplified scattering coefficient is derived, that is related to the surface conductivity and the electromagnetic impedance in vacuum. The results calculated by both Mie and Rayleigh formula for particles with a small size parameter are concordant. The charges carried on the surface of the particles increase the surface conductivity. When the surface conductivity reaches magnitude of millisiemens, it will have obvious effects. As the surface conductivity increases, the scattering efficiency will have bigger change. When the conductivity reaches a certain value, the ratio of scattering efficiency of the charged and neutral particles with a small size parameter tends to be stable. For the charged droplet, the ratio will tend to be twenty four which is related to the dielectric constant of the particles.
出处
《光学学报》
EI
CAS
CSCD
北大核心
2015年第5期368-374,共7页
Acta Optica Sinica
基金
国家自然科学基金(61172029
51206082
61302189)
关键词
散射
瑞利散射
电磁波散射
带电粒子
米氏散射
scattering Rayleigh scattering scattering of electromagnetic waves charged particle Mie scattering
