{"title":"雷击高空物体时自由空间电磁场的计算","authors":"Helin Zhou, R. Thottappillil, G. Diendorfer","doi":"10.1109/SIPDA.2013.6729189","DOIUrl":null,"url":null,"abstract":"We calculate vertical electric field and azimuthal magnetic field at different elevation angles and distances associated with lightning strikes a tall object. Simple and exact expressions for electromagnetic fields are derived when the current reflection coefficient at tall object top is zero and return stroke propagation speed in the lightning channel is equal to the speed of light. Further, we investigate the effects of current reflection coefficient at tall object top being not zero and the propagation speed is less than the speed of light (e.g., one half) on electromagnetic fields. Interestingly, we find that the vertical electric field has its largest peak value either at the smallest elevation angle or at the largest elevation angle. While for the azimuthal magnetic field, we note that its largest peak value is always at the smallest elevation angle or relatively small elevation angles.","PeriodicalId":216871,"journal":{"name":"2013 International Symposium on Lightning Protection (XII SIPDA)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0000,"publicationDate":"2013-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"1","resultStr":"{\"title\":\"Calculation of electromagnetic fields in free space when lightning strikes a tall object\",\"authors\":\"Helin Zhou, R. Thottappillil, G. Diendorfer\",\"doi\":\"10.1109/SIPDA.2013.6729189\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"We calculate vertical electric field and azimuthal magnetic field at different elevation angles and distances associated with lightning strikes a tall object. Simple and exact expressions for electromagnetic fields are derived when the current reflection coefficient at tall object top is zero and return stroke propagation speed in the lightning channel is equal to the speed of light. Further, we investigate the effects of current reflection coefficient at tall object top being not zero and the propagation speed is less than the speed of light (e.g., one half) on electromagnetic fields. Interestingly, we find that the vertical electric field has its largest peak value either at the smallest elevation angle or at the largest elevation angle. While for the azimuthal magnetic field, we note that its largest peak value is always at the smallest elevation angle or relatively small elevation angles.\",\"PeriodicalId\":216871,\"journal\":{\"name\":\"2013 International Symposium on Lightning Protection (XII SIPDA)\",\"volume\":\"24 1\",\"pages\":\"0\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2013-10-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"1\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"2013 International Symposium on Lightning Protection (XII SIPDA)\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1109/SIPDA.2013.6729189\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"2013 International Symposium on Lightning Protection (XII SIPDA)","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1109/SIPDA.2013.6729189","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
Calculation of electromagnetic fields in free space when lightning strikes a tall object
We calculate vertical electric field and azimuthal magnetic field at different elevation angles and distances associated with lightning strikes a tall object. Simple and exact expressions for electromagnetic fields are derived when the current reflection coefficient at tall object top is zero and return stroke propagation speed in the lightning channel is equal to the speed of light. Further, we investigate the effects of current reflection coefficient at tall object top being not zero and the propagation speed is less than the speed of light (e.g., one half) on electromagnetic fields. Interestingly, we find that the vertical electric field has its largest peak value either at the smallest elevation angle or at the largest elevation angle. While for the azimuthal magnetic field, we note that its largest peak value is always at the smallest elevation angle or relatively small elevation angles.