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| 不同方位甚低频电磁波衰减的初步研究* | |
| 引用本文： | 徐维东,张学民,李忠,赵庶凡,王贺生.不同方位甚低频电磁波衰减的初步研究*[J].地震,2016,36(2):60-67. |
| 作者姓名： | 徐维东 张学民 李忠 赵庶凡 王贺生 |
| 作者单位： | 1.防灾科技学院,河北三河 065201; 2.中国地震局地震预测研究所,北京 100036; 3.河北省地震局秦皇岛中心台,河北秦皇岛 066000 |
| 基金项目： | 中央高校基本科研业务费研究生科技创新基金项目(ZY20150309)和科技部国际合作项目(2014DFR21280)联合资助 |
| 摘 要： | 利用2005—2010年DEMETER卫星记录NWC发射站的19.8kHz电场功率谱数据,采用统计和线性拟合等方法,研究了NWC站发射的电磁波在顶部电离层及磁共轭区激发的电场效应及其在不同方位的衰减特性。结果发现:(1)在NWC发射站上空,卫星记录电场呈椭圆状扩散分布,电场最强中心点位置相对地面人工源位置有一定偏移;(2)研究区上空电场北部衰减梯度最小,东部衰减梯度最大;(3)在其磁共轭区,南部电场衰减梯度最小,北部衰减梯度最大。综合分析认为人工源(NWC)发射的VLF电磁波传播到电离层高度后,受地磁场影响,电磁波主要沿磁力线方向传播,空间电场最强中心点位置相对发射站的位置发生偏移,向磁赤道方向倾斜,而且偏于磁赤道方向的电场衰减梯度最小。 |
| 关 键 词： | 电磁波衰减 线性拟合 VLF电场 NWC发射站 DEMETER卫星 |
| 收稿时间： | 2015-09-09 |
| 修稿时间： | 2015-12-23 |
Relationship between Very Low Frequency Electromagnetic Wave Attenuation and Directions |
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| XU Wei-Dong,ZHANG Xue-min,LI Zhong,ZHAO Shu-fan,WANG He-sheng.Relationship between Very Low Frequency Electromagnetic Wave Attenuation and Directions[J].Earthquake,2016,36(2):60-67. | |
| Authors: | XU Wei-Dong ZHANG Xue-min LI Zhong ZHAO Shu-fan WANG He-sheng |
| Institution: | 1. Institute of Disaster Prevention,Hebei Sanhe 065201,China; 2. Institude of Earthquake Science, CEA,Beijing100036,China; 3. Qinhuangdao Central Station,Hebei Qinghuangdao 066000,China |
| Abstract: | Based on power spectral density data of electric field at 19.8kHz recorded by the DEMETER satellite during 2005—2010from NWC transmitter in Australia,the spatial distribution of the electric field at topside ionosphere and its magnetic conjugate region excited by NWC and its attenuation features at different directions by using statistical analysis and linear fitting methods are studied.The results show that,(1)at the topside ionosphere above NWC,the electric field recorded by satellite exhibits elliptical dispersion,and the position of maximal electric field center drifts to north and east relative to NWC;(2)the attenuation gradient in northern direction studied region is the smallest in four directions,and the east one is the largest;(3)at magnetic conjugate region,the attenuation gradient at south direction is the smallest,but the north one is the highest. The comprehensive analysis illustrates that,when the VLF electromagnetic wave from NWC transmitter penetrates into ionosphere,it will be controlled by geomagnetic field and mainly propagates along the magnetic power line,so the maximal center of electric field will drift to magnetic equator,and the attenuation gradient at equator-ward direction will be the smallest. |
| Keywords: | VLF electric field NWC transmitter Attenuation coefficient DEMETER satellite |
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