The exact dimensions of the transmitters or receivers used to model FEM data are defined within a transmitter or a receiver file, respectively; i.e. transmitters are defined within a transmitter file and receivers are defined within a receivers file. Because transmitters and receivers are both defined as closed loops made up of wire segments, the format of the transmitter and receiver files is identical.

Note

• Bolded entries are fixed flags recognized by the Fortran codes and blue hyperlinked entries are values/regular expressions specified by the user

3.3.5.1. Format¶

The lines of a transmitter/receiver file are formatted as follows:

ID $$\;$$ N $$\;$$ 1
$$\;\;\; x_1 \; y_1 \; z_1$$
$$\;\;\;\;\;\;\;\; \vdots$$
$$\;\; x_N \; y_N \; z_N$$
ID $$\;$$ N $$\;$$ 1
$$\;\;\; x_1 \; y_1 \; z_1$$
$$\;\;\;\;\;\;\;\; \vdots$$
$$\;\; x_N \; y_N \; z_N$$
ID $$\;$$ N $$\;$$ 1
$$\;\;\; x_1 \; y_1 \; z_1$$
$$\;\;\;\;\;\;\;\; \vdots$$
$$\;\; x_N \; y_N \; z_N$$

3.3.5.2. Parameter Descriptions¶

• ID: A unique index number for the transmitter or receiver. The index numbers should be increasing.

• N: The number of points defining the transmitter/receiver.

• 1: As of May 2018, a flag value of 1 is entered here. In future iterations of the code, this entry may be related to additional functionality.

• $$\mathbf{x_i \;\; y_i \;\; z_i}$$: Denotes the X (Easting), Y (Northing) and Z (elevation) locations for nodes defining transmitter/receiver.

• Loop transmitter/receiver: When defining a loop transmitter or receiver, you must close the loop; e.g. the fist and last nodes must be at the same locations. The transmitters and receivers are defined in a left-handed (clockwise) manner. For example, a horizontal loop must be defined in a clockwise manner for its dipole moment to be in the vertical direction. If a closed loop is used to define a receiver, the corresponding data are the magnetic field in units A/m.

• Wire transmitter/receiver: If the first and last nodes are not in the same place, the user will define a grounded receiver which measures the electric field. The grounded loop can be more than one segment long. In this case, the corresponding data are the electric field in units V/m.