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Problem with surface integral of the elerctric energy density
Posted 23 nov. 2018, 13:24 UTC−5 Electromagnetics, Low-Frequency Electromagnetics Version 5.2a 1 Reply
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Hi,
I have a simple model of two metal electrodes (cubes) in vacuum box (also cube). In the simulation I calculate the electric field using the electrostatic module. Then I want to calculate a surface integral of the electric field on one boundary (face) of one of the cubes (result should is in [J/m]).
The problem is that I am geting diferent numbers when integrating over the energy density (es.We) compared to integrating over (es.normE* es.normD* 0.5), which should be the same by definition. The difference is exactly factor of 4 (integral over esWe is bigger)!
When I do the domain integration over the whole vaccum box (total energy in [J]) I get the same numbers (as expected) when using both expressions.
What am I missing? Which value of the surface integral should I believe?
(I need the value of the surface integral to get a "thickness density" of the electric field energy, which I will use for my next calculations).
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The problem seems to be even deeper. The factor of 4 appears already when exporting the values of the energy density calculated by different expressions (see attachment).
Any help?
Attachments: