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What kinds of physics to be applied to stationary electric field simulation between two electrodes?

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Hello.

I'm pretty new in COMSOL and I've tried to simulate the electric field distribution between two electrodes in stationary solution.

There is some dielectric material between two electrodes and let's assumed that the whole system is inside the vacuum.

This should be pretty simple simulation and the followings are the list of the physics I included.

1. Charge conservation (for all domains)
2. Zero charge (for all boundaries except for the electrodes)
3. Initial values (for all domains as electric potential V = 0)
4. Electric potential (for two electrodes boundaries)

Simulation looks finely run but I'm wondering there might be additional physics I have to apply like the
space charge density and ground or etc.

In some tutorial the space charge density and ground are applied to very similar simulation but I didn't see the reason why I have to use such physics. The simulation runs without them.

For ground Should I apply it to dielectric material? Is it necessary?

And what does initial values play? I'm not talking about time-varying solution and I thought It is not necessary but can't remove it. It looks default.

Please help me clarify my vision toward the right simulation.



2 Replies Last Post 17 juin 2014, 20:53 UTC−4

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Posted: 1 decade ago 17 juin 2014, 09:25 UTC−4
'Zero charge' condition is the same as setting charge density to zero in a 'Space charge' condition.
The same goes for a 'ground' condition and an 'Electric potential' condition with the potential set to zero.
So with either setting the simulation should work.

Do not put your dielectric to ground, that would only be physical for conductors.

Initial values are included by default. It does not make a difference for a steady state simulation, maybe it is used as the first guess by the solver. You cannot remove them but for steady state the actual value is not important I believe.
'Zero charge' condition is the same as setting charge density to zero in a 'Space charge' condition. The same goes for a 'ground' condition and an 'Electric potential' condition with the potential set to zero. So with either setting the simulation should work. Do not put your dielectric to ground, that would only be physical for conductors. Initial values are included by default. It does not make a difference for a steady state simulation, maybe it is used as the first guess by the solver. You cannot remove them but for steady state the actual value is not important I believe.

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Posted: 1 decade ago 17 juin 2014, 20:53 UTC−4
Oh I got it!

It seems my physics should work fine.

Thanks! Hopefully I'll get clean result after upgrading my memory:)

Oh I got it! It seems my physics should work fine. Thanks! Hopefully I'll get clean result after upgrading my memory:)

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