Electrostatic Particle In Cell (esPtclInCellT.pre)


electrostatics, particle in cell, sheath, box bounding

Problem description

This electrostatic particle in cell example computes the electrostatic potential and fields in a box with conducting walls and particle absorbers and with an immobile, background neutralizing charge density. The electrons move to the wall by the potential, creating a sheath.

This simulation can be performed with a VSimBase license.

Opening the Simulation

The electrostatic particle in cell example is accessed from within VSimComposer by the following actions:

  • Select the NewFrom Example… menu item in the File menu.
  • In the resulting Examples window expand the VSim for Basic Physics option.
  • Expand the Basic Examples (Text-based setup) option.
  • Select “Electrostatic Particle in Cell (Text-based setup)” 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.

The basic variables of this problem should now be alterable via the text boxes in the left pane of the Setup Window, as shown in Fig. 157.

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Fig. 157 Setup Window for the electrostatic particle in cell example.

Input File Features

The input file allows one to choose the simulation dimension, domain size, resolution (number of cells in each direction), electron temperature (eV), electron density, voltage, ratios of cyclotron frequencies to plasma frequency and electron marcroparticles per cell.

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.” A snapshot of the simulation run completion is shown in Fig. 158.
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Fig. 158 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.

To view the electric potential

  • Expand the Scalar Data
  • Select phi
  • Move the dump slider to the right to Dump 1

The potential in the visualization window resembles that shown in Fig. 159.

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Fig. 159 The Visualize Window showing the electric potential, phi, at dump 1.

Further Experiments

Change the plasma density and see whether the frequency in the histories changes.

Set BZRATIO to 1.0 to observe the upper-hybrid mode.

Set BXRATIO to 1.0 to observe both the plasma mode and the upper-hybrid mode.

Set a value to V_RIGHT to see how the potential distribution changes.

Change the parameter NDIM to 3 to see the potential in 3 dimensions. Note that this will take longer to simulate.