Poynting Vector: "S Points Radially Inward" Explained

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    Poynting vector Vector
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SUMMARY

The Poynting vector, which represents the flow of electromagnetic energy, points radially inward when a capacitor is being charged. This indicates that energy flows orthogonally from the surrounding space into the capacitor, where it is stored as an electric field within the dielectric material. During discharging, the Poynting vector points outward, and in a stable condition, it becomes null. This behavior is typical for systems like coils and capacitors, illustrating the dynamic nature of energy flow in electromagnetic fields.

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  • Understanding of electromagnetic theory
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  • Knowledge of the Poynting vector and its physical significance
  • Basic concepts of electric fields and dielectrics
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yannick^
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I have a question about the Poynting vector:

mit.edu/8.02t/www/materials/StudyGuide/guide13.pdf (page 44/51)

What is the physical interpretation of "S points radially inward". That seems kinda weird. Energy flows to the center?

cheers
 
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Couldn't find your exact page on the link...but yes, seems unusual but that is typical for Poynting vector...say, of a coil or capacitor being charged...the energy flows orthogonally into it from the surrounding space otside the coil.

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Yes.

It's not so weird after all: while being charged, the capacitor is storing energy in the form of the electrical field which is being "built" in the dielectric material inside it. Since the Poynting vector represents a flow of electromagnetic energy, it makes sense that during charging it will point towards the inside of the capacitor, and during discharging it will point outwards. In a stable condition of the capacitor, the Poyting vector will be null.
 

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