Importing COMSOL field maps
In this example, we use COMSOL Multiphysics to calculate the electric potential inside a GEM. A Matlab script for doing so is available in the directory Examples/Comsol/Comsol of the source tree. After having obtained the solution, we want to export it for use within Garfield++.
Complementary to the description given below, you can find instructions in this document (contributed by Irina Kempf).
Exporting a field map
As a first step, we save the mesh to a text file.
- Navigate in the tree to Mesh → Export.
- Choose a file name (file type ".mphtxt").
- Select: Export as second-order elements.
- Export.
Next, we export a map of the electric potential.
- Navigate to Results → Export → Data.
- Select the correct data set.
- Select expression "V".
- Choose a file name.
- Select data format "Spreadsheet".
- Select resolution "Custom".
- Select Lagrange order "2"
- Export.
Finally, we need to create a text file containing the relevant material properties. In this example, there are three materials: gas (domain 1) with dielectric constant ε = 1, polymer (domain 2) with dielectric constant ε = 4, and copper (domains 3 and 4). The text file should contain
- the number of materials,
- followed by the relative dielectric constants of each material,
- the number of domains and
- a list of domain indices and corresponding material indices (the latter starting with 0).
Our file should therefore look like this:
3
1 4 1e10
4
1 0
2 1
3 2
4 2
We can now import these files in Garfield++ using the class ComponentComsol. The necessary steps are essentially the same as the ones discussed in the Ansys GEM example.
The source code of an example program is available in the directory Examples/Comsol of the source tree.