# Electromagnetic Plane Wave (emPlaneWave.sdf)

Keywords:

electromagnetics, plane wave, periodic boundary conditions, wave launcher

## Problem Description

A linearly-polarized (with electric field in the z-direction) electromagnetic pulse with a sinusoidal amplitude on a plane wave is launched from the left side (x=0) to propagate in the x-direction. The transverse (y,z) boundary conditions are periodic.

This simulation can be performed with a VSimBase license.

## Opening the Simulation

The Electromagnetic Plane Wave example is accessed from within VSimComposer by the following actions:

• In the resulting Examples window expand the VSim for Basic Physics option.
• Expand the Basic Examples option.
• Select Electromagnetic Plane Wave and press the Choose button.
• In the resulting dialog, create a New Folder if desired, and press the Save button to create a copy of this example.

All of the properties and values that create the simulation are now available in the Setup Window as shown in Fig. 121. You can expand the tree elements and navigate through the various properties, making any changes you desire. The right pane shows a 3D view of the geometry, if any, as well as the grid, if actively shown. To show or hide the grid, expand the Grid element and select or deselect the box next to Grid.

Fig. 121 Setup Window for the Electromagnetic Plane Wave example.

## Simulation Properties

This example includes several constants for easy adjustment of simulation properties. Those include:

• AMPLITUDE: The amplutide of the plane wave
• WAVELENGTHS: The number of wavelengths inside the domain

There is a SpaceTimeFunction to define the plane wave that is launched with a Port Launcher boundary condition.

## Running the Simulation

After performing the above actions, continue as follows:

• Proceed to the Run Window by pressing the Run button in the left column of buttons.
• To run the file, click on the Run button in the upper left corner of the Logs and Output Files pane. You will see the output of the run in the right pane. The run has completed when you see the output, “Engine completed successfully.” This is shown in Fig. 122.

Fig. 122 The Run Window at the end of execution.

## Visualizing the Results

After performing the above actions, continue as follows:

• Proceed to the Visualize Window by pressing the Visualize button in the left column of buttons.

The electric and magnetic field components can be found in the scalar data variables of the data overview tab.

• Make sure the Data View drop down is set to Data Overview.
• Here you can see Variables. Expand the Scalar Data.
• Expand E
• Select E_z

Initially, no field will be seen, as one is looking at Dump 0, the initial dump, when no fields are yet in the simulation. Move the slider at the bottom of the right pane to see the electric field at different times. The final time is shown in Fig. 123.

Fig. 123 Visualization of plane wave as a color contour plot.

## Further Experiments

To see more wavelengths, change the value of the WAVELENGTHS variable. What happens to the waves when there are very few cells in a wavelength?

See the wave reflect off the right boundary by running for more time steps.

Try changing NDIM to 3 to see the how the simulation is uniform across the z- dimension.