Discussion Forum

Hello all,
I am learning COMSOL 4.1 and I reached a point where I am stuck.

I am trying to model the following scene in a3D geometry with the COMSOL electrostatics package:

A sphere of dielectric material A is placed on a substrate. Inside the sphere I place an electric point dipole.
The substrate B is dielectric, too, and has a thin surface layer C with a different dielectric constant. On top of the surface, surrounding the sphere is air. The substrate has a imaginary component of the dielectric constant.

I have made the substrate approx. 100 times larger than the sphere to aprox. infinity. Ultimately, I want to integrate over E^2 (E=electric field) in the absorbing dielectric substrate), but first I need to find the potential.

Now my problem is that beside the initial values I cannot change any other properties of the Electrostatics parameters. The boundary conditions seem to be "locked". Charge conservation is applied to all domains and for the E field COMSOL uses the constitutive relation of the relative permittivity. Zero charge applies to all outer boundaries and I cannot change it.

As a result I do not know what to change or how to approach the problem when the solver fails. I tried changing the mesh size, but that did not help.

How would you proceed?

Many Thanks for any suggestions!

Best,
james

PS:
I have attached the COMSOL file in case you are interested.