config["Domains"]

"Domains":
{
    "Materials":
    [
        ...
    ],
    "Postprocessing":
    {
        "Dielectric":
        [
            ...
        ],
        "Probe":
        [
            ...
        ]
    }
}

with

"Materials" : Array of material properties objects.

"Postprocessing" : Top-level object for configuring domain postprocessing.

"Dielectric" : Array of objects for postprocessing bulk dielectric loss.

"Probe" : Array of objects for postprocessing solution field values evaluated at a probe location in space.

domains["Materials"]

"Materials":
[
    // Material 1
    {
        "Attributes": [<int array>],
        "Permeability": <float or float array>,
        "Permittivity": <float or float array>,
        "LossTan": <float or float array>,
        "Conductivity": <float or float array>,
        "LondonDepth": <float>,
        "MaterialAxes": <array of float array>
    },
    // Material 2, 3, ...
    ...
]

with

"Attributes" [None] : Integer array of mesh domain attributes for this material.

"Permeability" [1.0] : Relative permeability for this material. Scalar or vector of 3 coefficients corresponding to each of "MaterialAxes".

"Permittivity" [1.0] : Relative permittivity for this material. Scalar or vector of 3 coefficients corresponding to each of "MaterialAxes".

"LossTan" [0.0] : Loss tangent for this material. Scalar or vector of 3 coefficients corresponding to each of "MaterialAxes".

"Conductivity" [0.0] : Electrical conductivity for this material, S/m. Activates Ohmic loss model in the material domain. Scalar or vector of 3 coefficients corresponding to each of "MaterialAxes".

"LondonDepth" [0.0] : London penetration depth for this material, specified in mesh length units. Activates London equations-based model relating superconducting current and electromagnetic fields in the material domain.

"MaterialAxes" [[1.0,0.0,0.0], [0.0,1.0,0.0], [0.0,0.0,1.0]] : Axes directions for specification of anisotropic material properties. Required to be unit length and orthogonal.

domains["Postprocessing"]["Dielectric"]

"Postprocessing":
{
    "Dielectric":
    [
        {
            "Index": <int>,
            "Attributes": [<int array>]
        },
        ...
    ]
}

with

"Index" [None] : Index of this lossy domain, used in postprocessing output files.

"Attributes" [None] : Integer array of mesh domain attributes for this lossy domain.

domains["Postprocessing"]["Probe"]

"Postprocessing":
{
    "Probe":
    [
        {
            "Index": <int>,
            "X": <float>,
            "Y": <float>,
            "Z": <float>
        },
        ...
    ]
}

with

"Index" [None] : Index of this probe, used in postprocessing output files.

"X" [None] : $x$-coordinate of this probe, specified in mesh length units.

"Y" [None] : $y$-coordinate of this probe, specified in mesh length units.

"Z" [None] : $z$-coordinate of this probe, specified in mesh length units.