Poynting energy flow in Eath's atmosphere?

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Discussion Overview

The discussion centers on the Poynting energy flow in Earth's atmosphere, particularly the interaction between electric and magnetic fields and their implications for energy transfer. Participants explore theoretical aspects, potential measurements, and related electromagnetic phenomena.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose that the electric field between the ionosphere and the ground, combined with the Earth's magnetic field, results in significant energy flow from west to east, as described by the Poynting theorem.
  • Calculations are presented, suggesting a Poynting vector magnitude of 54,00,000 W/m² based on specific electric and magnetic field values.
  • Questions are raised about the measurement of induced EMF across a copper rod placed in this energy flow, with concerns about the absence of a "sink" or "ground" for measurements.
  • Some participants express skepticism about whether the presence of electric and magnetic fields necessarily indicates a flow of power, suggesting that these fields could exist independently of power flow.
  • There are claims that in certain configurations, such as with a magnet attached to a Van de Graaff machine, energy can flow in closed loops without doing work on matter or changing field energy density.
  • Discussion includes the concept of angular momentum in field configurations and the potential for energy recovery under specific conditions.
  • Interest is expressed in the Heaviside component, with requests for additional resources and acknowledgment of difficulty in understanding existing literature.
  • Some participants speculate about the nature of EM waves generated during the operation of devices like the Van de Graaff machine and their potential role in everyday electrical phenomena.

Areas of Agreement / Disagreement

Participants express a mix of agreement and disagreement regarding the implications of the electric and magnetic fields, the nature of energy flow, and the existence of the Heaviside component. No consensus is reached on these topics.

Contextual Notes

Limitations include potential misunderstandings of the relationship between electric and magnetic fields and power flow, as well as the complexity of measuring induced EMF in the described scenarios.

Narayanan KR
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Poynting new.jpg

1.There is an electric field between ionosphere and ground, also Earth's magnetic field is perpendicular to this E field, hence by poynting theorem integrating E x H across the entire surface of Earth gives a great deal of energy flowing west to east.
2. |S| = (E X B)/u0 = (150 V/m X 0.045 T)/(1.25 X10^-6 H/m) = 54,00,000 W/m^2 !
3. Imagine keeping a copper rod along west-east, will there be a emf induced across the rod's ends ?, i think we can't measure this voltage because even the voltmeter is inside such an energy flow viz., there is no "sink" or "ground" to do the measurements
4.Are Earth currents because of soil intercepting this flow partially? all your opinions are welcomed. .
 
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Narayanan KR said:
View attachment 103601
1.There is an electric field between ionosphere and ground, also Earth's magnetic field is perpendicular to this E field, hence by poynting theorem integrating E x H across the entire surface of Earth gives a great deal of energy flowing west to east.
2. |S| = (E X B)/u0 = (150 V/m X 0.045 T)/(1.25 X10^-6 H/m) = 54,00,000 W/m^2 !
3. Imagine keeping a copper rod along west-east, will there be a emf induced across the rod's ends ?, i think we can't measure this voltage because even the voltmeter is inside such an energy flow viz., there is no "sink" or "ground" to do the measurements
4.Are Earth currents because of soil intercepting this flow partially? all your opinions are welcomed. .
Just because a volume of space contains E and H fields in a certain configuration, not sure that it necessarily means there is a flow of power. I suspect these fields can either be caused by a flow of power or can have a separate existence not caused by the flow of power. As an example, suppose I fix a magnet to a Van de Graaff machine. Is there then a flow of power under steady conditions?
 
tech99 said:
As an example, suppose I fix a magnet to a Van de Graaff machine. Is there then a flow of power under steady conditions?
Yes. There are closed loops of energy flowing around such a configuration. While the fields are maintained constant there is no work done on matter and no change in the field energy density. All of the energy flowing into a region also flows out.

Just as importantly this type of field configuration has angular momentum. Under the right conditions the field can be reduced to recover the energy and angular momentum.
 
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Mr Dale i want some more links on Heaviside Component.
I didn't find one except his own papers which are difficult to understand ...if you have one please share it with me
 
I have never heard of heaviside Component
 
Dale said:
Yes. There are closed loops of energy flowing around such a configuration. While the fields are maintained constant there is no work done on matter and no change in the field energy density. All of the energy flowing into a region also flows out.

Just as importantly this type of field configuration has angular momentum. Under the right conditions the field can be reduced to recover the energy and angular momentum.
Thank you, Dale. And I am supposing that when the V de G machine is switched on, whilst it builds up, an EM wave will be set up which feeds or builds the closed loops of energy. And at switch off, another EM wave is created which extracts that same energy. Similarly if the magnet is an electro magnet and is turned on and off.
As this EM wave is of a very low frequency, I am supposing that it is captive and not radiated.
I am very interested that a captive EM wave having a frequency of a fraction of a Hertz might be part of everyday electrical phenomena.
 

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