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Evaluate surface charge density on a plate capacitor

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Hi,

I am trying to evaluate the surface charge density on one plate of a parallel plate capacitor and using the Electrostatics module for this purpose. I have constructed a dummy model which just consists of a rectangular block, where one side is a terminal at 1V and the opposite side is grounded.

When I try to evaluate the surface charge density for plotting in the following manner "es.nD" I get an error:

Cannot evaluate expression.

Undefined variable.

  • Variable: comp1.es.nD

  • Geometry: geom1

  • Domain: 1

I have no trouble in plotting the normal component of the displacement field "es.Dy". But for the actual case that I'm trying to model, I need to evaluate the surface charge density at a flat interface inbetween a capacitor, so the term of interest to me would be: "up(es.Dy)-down(es.Dy)". And merely evaluating "down(es.Dy)" gives me the same error as above:

Cannot evaluate expression.

Failed to evaluate operator.

  • Operator: down

  • Geometry: geom1

  • Domain: 1

Could you kindly guide me what the correct method is to determine the surface charge density at an interface?

Thanks!

Best Regards, Deepankur Thureja



0 Replies Last Post Mar 25, 2020, 4:40 a.m. EDT
COMSOL Moderator

Hello Deepankur Thureja

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