Electromagnetic¶

Type:	enum
Range:	Cylindrical, Impedance, TangentialElectric, TangentialMagnetic
Default:	-/-
Appearance:	optional

This parameter fixes the type of boundary conditions for the electromagnetic field.

The following boundary types are allowed:

TangentialElectric: Fixes the tangential components of the electric field $\VField{E}$ by prescribing an “electric field strength” tensor field.
TangentialMagnetic: Fixes the tangential components of the magnetic field $\VField{H}$ by prescribing a “magnetic field strength” tensor field.
Impedance: This type is only implemented for time-harmonic problems. The electric field $\VField{E}$ and the magnetic field $\VField{H}$ are related by

$\begin{eqnarray*} \left( \sqrt{\varepsilon} \VField{E} - \sqrt{\mu} \VField{H} \right ) \times \pvec{n} & = & \left( \sqrt{\varepsilon} \VField{E}_{\mathrm{in}} - \sqrt{\mu} \VField{H}_{\mathrm{in}} \right ) \times \pvec{n}, \end{eqnarray*}$

where $\pvec{n}$ is the boundary’s normal and $\VField{E}_{\mathrm{in}}$ and $\VField{H}_{\mathrm{in}}$ are prescribed fields given by the user as input data. It is required that the permittivity, $\varepsilon,$ and permeability, $\mu,$ are isotropic.
Cylindrical: This type is obsolete and only included to guarantee downward compatibility. To define a cylindrical symmetric problem select the coordinate system type Cylindrical within the project definition (see here for the case of an electromagnetic scattering problem).

Note

The discussed parameter only defines the type of the boundary condition. The actual field values, e.g. $\VField{E}$ and $\VField{H}$ , are passed in the source file sources.jcm.

Example

The following definitions in the files boundary_conditions.jcm and sources.jcm enforce zero tangential components of the electric field on a boundary “”BoundaryId”” equal to 5:

# define type of the boundary condition in boundary_conditions.jcm
BoundaryCondition {
  BoundaryId = 5
  Electromagnetic = TangentialElectric
}

# set the actual field value in sources.jcm
...
Source {
  BoundaryId = 5
  ElectricFieldStrength = [0.0 0.0 0.0]
}

Note

In the above example all components of the electric field are prescribed. However, the normal component (with respect to the regarded boundary) will not be used.

When solving for multiple right hand sides (cf. SourceBag) the boundary condition type remains fix. However, it is possible to specify different field values for each right hand side on the boundary:

# sets individual boundary field values for multiple right hand sides


# rhs 1
SourceBag
  Source {
    BoundaryId = 5
    ElectricFieldStrength = ...
  }
}
...
# rhs n
SourceBag
  Source {
    BoundaryId = 5
    ElectricFieldStrength = ...
  }
}