Skin Effect Not Visible in Electric Currents (EC) Frequency Domain Simulation

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Hi everyone,

I'm trying to visualize the skin effect in a tungsten cylinder using the Electric Currents (EC) interface in the frequency domain. I’ve added a Terminal and a Ground, and set the excitation frequency to 1 MHz.

I also refined the mesh near the boundaries using Boundary Layers (to capture the skin depth), but the current density distribution still looks uniform it behaves as if it’s a DC simulation.

Could anyone explain:

  • How to correctly make the skin effect visible in EC (without switching to the Magnetic Fields or EM Waves interface)?

  • Whether this setup can actually capture the skin effect, or if the EC interface inherently behaves as a low-frequency (quasi-static) solver?

Thanks in advance!


3 Replies Last Post 2025/11/12 9:29 GMT-5
Edgar J. Kaiser Certified Consultant

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Posted: 1 day ago 2025/11/11 13:09 GMT-5

Hi Imke,

the skin effect results from induction currents in the conductor, so ec-physics cannot account for it. You need mf in case the structure is much smaller than the wavelength or emw if the structure is bigger than 1/10 of the wavelength. This a coarse rule of thumb.

Cheers Edgar

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Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Hi Imke, the skin effect results from induction currents in the conductor, so ec-physics cannot account for it. You need mf in case the structure is much smaller than the wavelength or emw if the structure is bigger than 1/10 of the wavelength. This a coarse rule of thumb. Cheers Edgar

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Posted: 12 hours ago 2025/11/12 5:11 GMT-5

Hi Edgar,

Thanks for your reply. I understand that EC cannot capture the skin effect and that I should use MF or EMW depending on the frequency.

In my case, I would like the current to enter at a single point at one end of a cylinder and exit at a single point at the other end, rather than being distributed over the entire surface.

Could you explain how to set up MF in COMSOL to specify exact input and output points for the current, without using a volume or surface current density? Is there a way to emulate a point injection and collection of current in MF?

Thanks in advance!

Hi Edgar, Thanks for your reply. I understand that EC cannot capture the skin effect and that I should use MF or EMW depending on the frequency. In my case, I would like the current to enter at a single point at one end of a cylinder and exit at a single point at the other end, rather than being distributed over the entire surface. Could you explain how to set up MF in COMSOL to specify exact input and output points for the current, without using a volume or surface current density? Is there a way to emulate a point injection and collection of current in MF? Thanks in advance!

Edgar J. Kaiser Certified Consultant

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Posted: 8 hours ago 2025/11/12 9:29 GMT-5

Hi Imke,

I recommend to have a look into the application library to learn about how to set up single conductor coils in mf or ports in emw. Point connections are mostly not recommended because they may result in singularities.

Cheers Edgar

-------------------
Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Hi Imke, I recommend to have a look into the application library to learn about how to set up single conductor coils in mf or ports in emw. Point connections are mostly not recommended because they may result in singularities. Cheers Edgar

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