Ten-Moment, Two-Fluid Shock (tenMomentShock.pre)¶

Problem description¶

This example simulates a two-fluid shock where the ions use the 10 moment plasma model and the electrons use the 5 moment model.

This simulation can be performed with a USimHEDP license.

Creating the run space¶

The Ten-Moment, Two-Fluid Shock example is accessed from within USimComposer by the following actions:

• Select the New from Template menu item in the File menu.
• In the resulting New from Template dialog, expand USimHEDP: High Energy Density Plasmas.
• Select Ten-Moment, Two-Fluid Shock and press the Choose button.
• In the Choose a name for the new runspace dialog, press the Save button to create a copy of this example in your run area.
• Press the Save And Process Setup button in the upper right corner of the Editor pane.

The basic example variables are editable in the Editor pane of the Setup window. After any change is made, the Save and Process Setup button must be pressed again before a new run commences.

Input file features¶

The following parameters can be varied to study different plasmas:

• CFL - used in the simulation
• SCALE - scales the density and pressure keeping the temperature and acoustic speed constant
• NCELLS - number of cells in the simulation
• TEND - final simulation time
• NUMDUMPS - number of data dumps during the simulation
• XMAX - size of the domain

Running the simulation¶

After performing the above actions, continue as follows:

• Proceed to the Run window as instructed by pressing the Run icon in the workflow panel.
• To run the simulation, click on the Run button in the upper right corner of the Logs and Output Files pane.

You will also see the engine log output in the Logs and Output Files pane. The run has completed when you see the output, “Engine completed successfully.”

Visualizing the results¶

After performing the above actions, continue as follows:

• Proceed to the Visualize window as instructed by pressing the Visualize icon in the workflow panel.
• Press the Open button to begin visualizing.
• In the Data View dropdown menu, select 1-D Fields.
• The electron density shown in Fig. 90 can be visualized by clicking on electrons_0 in Plot 0.

Similarly other parameters such as magnetic field can be visualized. The description of output parameters follows

• electrons_0 through electrons_4 the electron density, momentum density and energy density
• ions_0 through ions_9 the ion density, momentum density and 6 components of anisotropic energy density
• em_0 through em_5 are the E and B fields

Figure 90: Visualization of electron mass density for the Ten-Moment, Two-Fluid Shock example.

Further experiments¶

1. Increase XMAX and TEND by the same factor to see how the solution evolves. Unlike the Euler equations and ideal MHD, the solution is not invariant with the scale of the system.