Electromagnetic Power

2021 ◽  
pp. 38-59
Author(s):  
Alexander I. Petroianu
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
J.-F. Ripoll ◽  
T. Farges ◽  
D. M. Malaspina ◽  
G. S. Cunningham ◽  
E. H. Lay ◽  
...  

AbstractLightning superbolts are the most powerful and rare lightning events with intense optical emission, first identified from space. Superbolt events occurred in 2010-2018 could be localized by extracting the high energy tail of the lightning stroke signals measured by the very low frequency ground stations of the World-Wide Lightning Location Network. Here, we report electromagnetic observations of superbolts from space using Van Allen Probes satellite measurements, and ground measurements, and with two events measured both from ground and space. From burst-triggered measurements, we compute electric and magnetic power spectral density for very low frequency waves driven by superbolts, both on Earth and transmitted into space, demonstrating that superbolts transmit 10-1000 times more powerful very low frequency waves into space than typical strokes and revealing that their extreme nature is observed in space. We find several properties of superbolts that notably differ from most lightning flashes; a more symmetric first ground-wave peak due to a longer rise time, larger peak current, weaker decay of electromagnetic power density in space with distance, and a power mostly confined in the very low frequency range. Their signal is absent in space during day times and is received with a long-time delay on the Van Allen Probes. These results have implications for our understanding of lightning and superbolts, for ionosphere-magnetosphere wave transmission, wave propagation in space, and remote sensing of extreme events.


2013 ◽  
Vol 340 ◽  
pp. 493-496
Author(s):  
Gang Ye

Using energy-harvesting technology can make the work scope of passive radio frequency identification tag to achieve the maximum .The study put forward to collecting light from the solar cell share tag antenna area, that provides the power source except from the reader receive to electromagnetic power ,which to activate the label circuit. In order to make solar cell to the influence of the tag antenna to minimum ,so optimize it with electromagnetic simulation on its position .The collected dc power could convert into the radio frequency with the efficient E-class oscillator , as well as it could flow into the radio frequency identification tag terminal with the aid of the proper designed coupled circuit .The oscillation frequency is selected on the principle of not affecting the operation of label back scattering .The presented oscillator is showed in the simulations .The E-class oscillator is used together with other forms of collection technology ,such as thermoelectric collect machine.


2020 ◽  
Author(s):  
gaobiao xiao

<p>Poynting theorem plays a very important role in analyzing electromagnetic phenomena. The electromagnetic power flux density is usually expressed with the Poynting vector. However, since Poynting theorem basically focuses on the power balance in a system, it is not so convenient in some situations to use it for evaluating the electromagnetic energies. The energy balance issue for time varying fields is revisited in this paper, and a set of energy balance equations are introduced, and a modified method for evaluating power flux is proposed.</p>


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