Reduced Problem

In this tutorial example we utilize the fourfold mirror symmetry of the geometrical layout of previous example to reduce the computational domain to a quarter of its original size:

The symmetry axes of the computational domain require a user-defined boundary condition to select the desired mode symmetry. In the layout file we assign Class=Mirror to the boundary segments to indicate geometrical mirroring. JCMsuite will automatically expand the mesh and solution to the unfolded sheet. For electromagnetic simulations there are two possible choices: either the tangential component of the electric or magnetic field is set to zero (cf. MirrorSymmetry for more details). Here we select a mode with has MagneticSymmetric boundary conditions along both mirror planes. Thus in the project.jcmp file we specify:

SelectionCriterion {
   MirrorSymmetry = [MagneticSymmetric,MagneticSymmetric]

Combinations of MagneticSymmetric and ElectricSymmetric for both symmetry axes give rise to the full spectrum of modes.

Alternatively it is possible to selectively define boundary conditions as well. This requires assigning a BoundaryId in the layout.jcm file. The approriate locations in the file are commented out. Further more a boundary_conditions.jcm file must be created with ``BoundaryCondition``entries for each domain boundary. A possible configuration is shown below:

BoundaryCondition {
  BoundaryId = 1
  Electromagnetic = TangentialElectric
}

BoundaryCondition {
  BoundaryId = 2
  Electromagnetic = TangentialElectric
}

Once computed, JCMview can show the unfolded intensity and vector field of a computed mode:

In the vector plot we observe that the electric field vectors on the boundary are normal to the symmetry planes, hence their tangential component is zero as specified by the MagneticSymmetric or TangentialElectric boundary condition.