5.2.2. Forward Modeling

Here, the code h3dtd_v2.exe and the input file h3dtd.inp (see format) are used to forward model SAM data for a large loop transmitter on the Earth’s surface. In this case, the Earth’s field has an inclination of -60 degrees and a declination of 45 degrees; i.e. coming out of the Earth and pointing towards the Northwest. Files relevant to this part of the example are in the sub-folder fwd. For this example, we use the model that was created in the example “create model”. Before running this example, you may want to do the following:

• Download and open the zip folder containing the entire H3DTD v2 example (if not done already)

• Learn how to run code from command line

• Learn the format of the input file

To forward model the data, the following input file was used:

H3DTD v2 forward models the projection of the anomalouus H-field along the direction of the Earth’s magnetic field. Below, we show SAM data at 0.0001 s, 0.001 s and 0.01 due to step-off excitation.