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The mu-metal material has no permeability assigned, so probably 1 is used.

Thank Edgar,

Okay, so Im a little confused apologies,

The physics I use does it not require a permeability value? I tried assinging the shielding geomteries as Air and I get the exact same results as just MuMetal or any other material. I dont get how COMSOL is using air as a geometrical shield?

So I tried adding material property for MuMetal and changed permeability to 1000, but it is still showing me the same results.

Im really new to COMSOL and very much confused as to what to do.

Thank you so much for replying, feels like some light at the end of the tunnel!

Just saw that the mu-metal thing is in a 'free space' node. It needs to be in an Ampere's law node. And of course the mf physics requires relative permeability. Check magnet examples in the application library.

YEs!

It worked when I added the amperes law, there is definitely a change in the result!

Im sorry for my following question because I know its basic,

but with regards to amperes law node addition, I looked at the governing equation, and it has a current input. My physics is weak, but is it because the permanent magnet is inducing a current in the MuMetal material?

Because I don't have any current in this system as of now, but electric fields are related to magnetic fields, so is the permanent magnet inducing a current flow in the MuMetal?

Also, for the amperes law node it says "amperes law in solids", is that correct? I remember sometimes it just says amperes law, is there a reason for this distinction?

Finally, if I now was to add a coil to this system and used different physics to simulate current flowing in a coil, can I still model the permanent magnets with the simple MFNC or will I have to add it to the other physics for coils and electromagnets?

Also, I checked the permanent magnets example and did find much about using amperes law, could you link me to the one perhaps? if not too much trouble, you have done so much for me already!

You have been so helpful, thank you so much Edgar! Legend!

Best

Your model is already using mf physics, not mfnc. mf accounts for induced currents, that is why the current equation is there. And you can add coils in mf. Regarding physics node properties, please check the documentation. Check examples and the documentation about coils. They can be tricky.

Cheers Edgar

Awesome!

Thank you so much,

Yes my mistake, Im using mf, I was using mfnc first but switched. This makes sense.

Im going through the example of coils, and hopefully I can manage to do something simple.

I really appreciate your support so much Edgar! Have a lovely Sunday.

Best wishes, F