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I am trying to find the bound modes of a particular WGM, similar to the Application found here: https://www.comsol.com/model/whispering-gallery-mode-resonator-90741. Because my structure is quite large (~mm scale), I have decided to use the Beam Envelopes interface instead of the frequency domain interface. When I run the simulation, I get an error for an undefined variable lambda that I cannot find anywhere in the model. Is there another undefined parameter that I need to work with? Note that the geometry is imported from another .mph file that I was originally working with.

Edit 17.4.2024: The issue seems to be purely in plotting the results. I am able to execute the solver completely without error, although I am not sure if it is storing valid solutions. When I try to plot a particular function, I get the error I have screenshotted above (pasted here so that others can read it)

I'm assuming this is some sort of stack trace, but as I am new to comsol I am not entirely sure how to read it.

Undefined variable. - Variable: lambda - Geometry: geom1 - Domain: 7 Failed to evaluate variable. - Variable: freq - Defined as: ((-0.5)lambda)/(pii) Failed to evaluate variable. - Variable: comp1.ewbe.freq - Defined as: freq Failed to evaluate variable. - Variable: comp1.ewbe.omega - Defined as: (2pi)comp1.ewbe.freq Failed to evaluate variable. - Variable: comp1.ewbe.iomega - Defined as: comp1.ewbe.omegai Failed to evaluate variable. - Variable: comp1.ewbe.k0 - Defined as: (comp1.ewbe.iomegasqrt(mu0_constepsilon0_const))/i Failed to evaluate variable. - Variable: comp1.ewbe.phi1 - Defined as: comp1.ewbe.k0comp1.ewbe.posz Failed to evaluate variable. - Variable: comp1.ewbe.expPhi1 - Defined as: exp((-i)comp1.ewbe.phi1) Failed to evaluate variable. - Variable: comp1.ewbe.E1z - Defined as: comp1.ewbe.expPhi1((comp1.E1rcomp1.pml1.T31)+(comp1.E1zcomp1.pml1.T33)) Failed to evaluate expression. - Expression: comp1.ewbe.E1z - Plot: Electric Field