Discussion Forum

In the Model Builder: Right-click Results. Select 3D plot group. Right-click 3D plot group. Select Arrow Volume (or if you prefer, Arrow Surface). For the x, y, and z components, enter the x, y, and z components of the magnetic field. Choose and set other relevant plot settings to make the plot appear as you wish. If you wish to animate this plot, go back to the Model Builder and right-click Export. Choose Animation --> Player (you can choose File if you prefer). In the Settings window, under Scene, and Subject: Select your 3D Plot group. If this is a frequency domain model and you wish to animate over phase, then under Animation Editing, choose Sequency type: Dynamic data extension. If it is a time-domain model, choose something else (like stored solutions, result parameter, etc.) I suspect you will now be able to figure out the rest.

Thank you for your quick response！ What I mean is that there is no existing expression in the arrow volume that expresses the tendency of the magnetic field in the cavity to move. This means that my magnetic field as a whole keeps rotating to the right as time changes, just like a clock or a turntable. I want to visualize this rotation.

I'm not sure what you mean. I use animations all the time, to visualize the rotation of magnetic fields. I've attached a related example (an animated .gif file), showing rotating magnetic fields in a circularly polarized EM wave, prepared exactly in the manner I described. Would you agree that this is a visualization of a rotating magnetic field ?

Thanks for your response and examples, I mean how to represent this rotation of field strength through a still picture as I am doing academic writing. Animation cannot be included in the paper. So I'm trying to find an expression in the arrow volume to visualize the rotation of the magnetic field. But I tried all the existing expressions provided by comsol and found no arrow that can represent the rotation of the magnetic field.

Ah. Well then, you may wish to consider alternative ways to represent/describe the polarization state of your EM fields. But bear in mind that plotting such quanties may not help you in clearly explaining your physics to other people who may be unfamiliar with the rather specialized terminology involved!
So, with that caveat, see: https://en.wikipedia.org/wiki/Stokes_parameters https://en.wikipedia.org/wiki/Jones_calculus https://en.wikipedia.org/wiki/Unpolarized_light#Poincar%C3%A9_sphere