scholarly journals A Comprehensive Study on the Improved Radio-Frequency Magnetic Field Measurement for the Initial Upward Leader of a Negative Rocket-Triggered Lightning Flash

2021 ◽  
Vol 13 (8) ◽  
pp. 1533
Author(s):  
Tao Shi ◽  
Gaopeng Lu ◽  
Yanfeng Fan ◽  
Xiao Li ◽  
Yang Zhang
Keyword(s):  
Magnetic Field ◽  
Radio Frequency ◽  
Field Measurement ◽  
Magnetic Sensor ◽  
Magnetic Field Measurement ◽  
Quiet Period ◽  
Lightning Current ◽  
Initial Stage ◽  
Frequency Magnetic Field ◽  
Triggered Lightning

The spectrum analysis of the lightning current in the experiment campaign of 2019 reveals that the lightning current waveform contains rich medium-frequency (MF) radiation signals in the initial stage. However, there is a lack of resolution for MF signals by using conventional magnetic sensors. The bandwidth of radio-frequency magnetic field measurement is improved by extending to 20 kHz–1.2 MHz in the Guangdong Comprehensive Observation Experiment on Lightning Discharge (GCOELD). During the previously noticed “quiet period” that can only maintain the upward propagation with relatively small-scale breakdown, magnetic pulses of quiet period (MPQPs) are discerned more clearly than the previous experiment in GCOELD. Aided by the improvement of a magnetic sensor, this paper captures richer magnetic field signals radiated from the weak discharge of the precursory phage than previous experiments in GCOELD. The analysis shows that both aborted UPLs and UPLs are caused by weak discharge pulses called initial precursor pulses (IPPs), which are very similar to the amplitude of the streamer discharge obtained in the laboratory. In summary, the signals detected by an improved magnetic sensor will provide an important reference for exploring the pulse characteristics of the whole discharge process and formation mechanism of the UPL in the initial stage of triggered lightning.

Vector magnetic field measurement based on magnetic fluid and high-order cladding-mode Bragg grating

2021 ◽  
Vol 143 ◽  
pp. 107264
Author(s):  
Junying Zhang ◽  
Fengyi Chen ◽  
Ruohui Wang ◽  
Xueguang Qiao ◽  
Haibin Chen ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fluid ◽  
Field Measurement ◽  
High Order ◽  
Bragg Grating ◽  
Magnetic Field Measurement ◽  
Vector Magnetic Field ◽  
Cladding Mode
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