Based on the MTLL lightning return stroke model,a two-dimensional cylindrical finite-difference time-domain( FDTD) model for underground horizontal electric field was established,and the effects of distance from light...Based on the MTLL lightning return stroke model,a two-dimensional cylindrical finite-difference time-domain( FDTD) model for underground horizontal electric field was established,and the effects of distance from lightning channel,depth,soil electrical conductivity and its distribution,and return stroke current on the characteristics of underground horizontal electric field were analyzed. The results showed that as long as the electrical conductivity of soil existed,the peak of underground horizontal electric field decreased with the increase in the horizontal distance from lightning channel. When the electrical conductivity of the upper soil was much smaller than that of the lower soil,the peak of corresponding horizontal electric field was larger than the electric field peak as the electrical conductivity of the upper soil was larger than that of the lower soil. When the electrical conductivity of the upper soil was less than that of the lower soil,the growth and decay of the horizontal electric field were faster than the growth and decay as the electrical conductivity of the upper soil was larger than that of the lower soil.展开更多
Electric and magnetic fields in time and frequency domain due to return stroke-lateral corona (RS-LC) system and re- cently discovered red sprites have been calculated. It has been found that the electric and magnetic...Electric and magnetic fields in time and frequency domain due to return stroke-lateral corona (RS-LC) system and re- cently discovered red sprites have been calculated. It has been found that the electric and magnetic fields due to return stroke and lateral corona system radiate in the very low frequency (VLF) region while due to sprites radiate in the ex- tremely low frequency (ELF) range. A comparison has been made between the radiations emitted due to RS-LC system and sprites in ELF (0 - 200 Hz) region. It has been found that the electric field i.e. radiation power generated due to sprites dominates in the ELF range and thus it is concluded that the red sprites as compared to the RS-LC system are the prominent source for the excitation of Schumann resonances in the earth-ionosphere waveguide.展开更多
依托中国气象局雷电野外科学试验基地人工引雷试验平台,利用自主研发的探测设备对发生于2023年7月18日的一次负极性人工触发闪电进行综合观测,获取了2次箭式先导-回击过程(RS1和RS2)高时间分辨、多参量互补的闪电电流、电场、磁场、甚高...依托中国气象局雷电野外科学试验基地人工引雷试验平台,利用自主研发的探测设备对发生于2023年7月18日的一次负极性人工触发闪电进行综合观测,获取了2次箭式先导-回击过程(RS1和RS2)高时间分辨、多参量互补的闪电电流、电场、磁场、甚高频(very high frequency,VHF)辐射以及X射线脉冲数据序列。结果表明:两次回击过程的下行先导进入气化钢丝通道及接地引起回击瞬间产生强烈的VHF和高能量X射线辐射,但其箭式先导发展速率存在较大差异,RS1先导发展速率达到10^(7) m·s^(-1)量级,对应较强的VHF辐射和连续型X射线脉冲;RS2先导发展速率达到10^(6) m·s^(-1)量级,相对于RS1二维发展速率低1个量级,VHF辐射和X射线脉冲相对较弱,且X射线呈分立脉冲特征;高能量X射线脉冲与先导沿钢丝通道下传接地引起回击的过程在时间上吻合,指示高能量X射线与回击启动过程间的直接关联,为揭示闪电回击阶段X射线的强场辐射机制提供了重要观测依据。展开更多
为研究当无线基站通信塔上避雷针遭受雷击时位于闪电通道附近天线的耦合效应,基于CST Studio Suite电磁仿真软件建立闪电通道-通信塔和工作在中国移动通信GSM1800/1900频段下的微带阵列天线的仿真模型。基于闪电回击电磁模型的继后回击...为研究当无线基站通信塔上避雷针遭受雷击时位于闪电通道附近天线的耦合效应,基于CST Studio Suite电磁仿真软件建立闪电通道-通信塔和工作在中国移动通信GSM1800/1900频段下的微带阵列天线的仿真模型。基于闪电回击电磁模型的继后回击过程,研究从天线极化方向讨论天线的雷击耦合特性以及天线单元连接由不同功分器构成的馈电网络进行组阵时阵列天线的雷击耦合特性。发现天线的耦合电压峰值与极化旋转角呈现线性关系,天线在垂直极化下的耦合电压比在水平极化下的耦合电压大得多;同时,对于通信塔上GSM频段的微带阵列天线,阵列天线的耦合电压受到馈电网络的影响,采用由威尔金森功分器构成的馈电网络进行组阵比采用由T型功分器构成的馈电网络进行组阵阵列天线的耦合电压更小。展开更多
文摘Based on the MTLL lightning return stroke model,a two-dimensional cylindrical finite-difference time-domain( FDTD) model for underground horizontal electric field was established,and the effects of distance from lightning channel,depth,soil electrical conductivity and its distribution,and return stroke current on the characteristics of underground horizontal electric field were analyzed. The results showed that as long as the electrical conductivity of soil existed,the peak of underground horizontal electric field decreased with the increase in the horizontal distance from lightning channel. When the electrical conductivity of the upper soil was much smaller than that of the lower soil,the peak of corresponding horizontal electric field was larger than the electric field peak as the electrical conductivity of the upper soil was larger than that of the lower soil. When the electrical conductivity of the upper soil was less than that of the lower soil,the growth and decay of the horizontal electric field were faster than the growth and decay as the electrical conductivity of the upper soil was larger than that of the lower soil.
文摘Electric and magnetic fields in time and frequency domain due to return stroke-lateral corona (RS-LC) system and re- cently discovered red sprites have been calculated. It has been found that the electric and magnetic fields due to return stroke and lateral corona system radiate in the very low frequency (VLF) region while due to sprites radiate in the ex- tremely low frequency (ELF) range. A comparison has been made between the radiations emitted due to RS-LC system and sprites in ELF (0 - 200 Hz) region. It has been found that the electric field i.e. radiation power generated due to sprites dominates in the ELF range and thus it is concluded that the red sprites as compared to the RS-LC system are the prominent source for the excitation of Schumann resonances in the earth-ionosphere waveguide.
文摘依托中国气象局雷电野外科学试验基地人工引雷试验平台,利用自主研发的探测设备对发生于2023年7月18日的一次负极性人工触发闪电进行综合观测,获取了2次箭式先导-回击过程(RS1和RS2)高时间分辨、多参量互补的闪电电流、电场、磁场、甚高频(very high frequency,VHF)辐射以及X射线脉冲数据序列。结果表明:两次回击过程的下行先导进入气化钢丝通道及接地引起回击瞬间产生强烈的VHF和高能量X射线辐射,但其箭式先导发展速率存在较大差异,RS1先导发展速率达到10^(7) m·s^(-1)量级,对应较强的VHF辐射和连续型X射线脉冲;RS2先导发展速率达到10^(6) m·s^(-1)量级,相对于RS1二维发展速率低1个量级,VHF辐射和X射线脉冲相对较弱,且X射线呈分立脉冲特征;高能量X射线脉冲与先导沿钢丝通道下传接地引起回击的过程在时间上吻合,指示高能量X射线与回击启动过程间的直接关联,为揭示闪电回击阶段X射线的强场辐射机制提供了重要观测依据。
文摘为研究当无线基站通信塔上避雷针遭受雷击时位于闪电通道附近天线的耦合效应,基于CST Studio Suite电磁仿真软件建立闪电通道-通信塔和工作在中国移动通信GSM1800/1900频段下的微带阵列天线的仿真模型。基于闪电回击电磁模型的继后回击过程,研究从天线极化方向讨论天线的雷击耦合特性以及天线单元连接由不同功分器构成的馈电网络进行组阵时阵列天线的雷击耦合特性。发现天线的耦合电压峰值与极化旋转角呈现线性关系,天线在垂直极化下的耦合电压比在水平极化下的耦合电压大得多;同时,对于通信塔上GSM频段的微带阵列天线,阵列天线的耦合电压受到馈电网络的影响,采用由威尔金森功分器构成的馈电网络进行组阵比采用由T型功分器构成的馈电网络进行组阵阵列天线的耦合电压更小。
