Electromagnetic Energy Density and Poynting Vector of a Relativistic Oscillator

2021 ◽  
pp. 3-12
Author(s):  
Geoffrey Brooker

“Electromagnetic energy” takes a hard look at the reasoning by which energy density and energy flow (Poynting vector) are deduced from Maxwell's equations. What can be proved and what, lacking proof, can be usefully said? It is argued that the conventional division of energy into density and flow is unproven but does not mislead. Picture of a pillbox.


2021 ◽  
Author(s):  
Soboh Alqeeq ◽  
Olivier Le Contel ◽  
Patrick Canu ◽  
Alessandro Retino ◽  
Thomas Chust ◽  
...  

<p>In the present work, we consider four dipolarization front (DF) events detected by MMS spacecraft in the Earth’s magnetotail during a substorm on 23rd of July 2017 between 16:05 and 17:19 UT. From their ion scale properties, we show that these four DF events embedded in fast Earthward plasma flows have classical signatures with increases of Bz, velocity and temperature and a decrease of density across the DF. We compute and compare current densities obtained from magnetic and particle measurements and analyse the Ohm’s law. Then we describe the wave activity related to these DFs. We investigate energy conversion processes via J.E calculations and estimate the importance of the electromagnetic energy flow by computing the divergence of the Poynting vector. Finally we discuss the electromagnetic energy conservation in the context of these DFs.</p>


2011 ◽  
Vol 36 (5) ◽  
pp. 675 ◽  
Author(s):  
Pi-Gang Luan ◽  
Yao-Ting Wang ◽  
Shuang Zhang ◽  
Xiang Zhang

2013 ◽  
Vol 423-426 ◽  
pp. 93-96
Author(s):  
Kang Bo Tan ◽  
Yi Chao Song ◽  
Tao Su ◽  
F. F. Fan ◽  
Hong Min Lu

This paper presents an analysis for electromagnetic energy in dispersive composite media based on classical electrodynamics. An investigation of the relation between reactance rate and electromagnetic energy derived from the Fosters theorem is conducted. The material energy of this kind is discussed in the frequency band of the left handed property. It is illustrated that the time average electromagnetic energy density is still positive even after an effect of dissipation is cancelled in the left handed band, which is reasonable in physics.


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