Cathode
Use the Cathode node to determine the boundaries from which the test particles should be released. This boundary should typically have a negative potential with respect to the grounded boundaries in the system.
cathode properties
Enter values or expressions for each of the following:
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Secondary emission coefficient γi (dimensionless). This is used to determine the threshold for whether the integrated Townsend coefficient along streamlines exceeds a specific value. The higher the value, the more likely electrical breakdown will occur. The default is 0.07, and values are typically between 0.001 and 0.4.
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Minimum field for sustained propagation Emin (SI unit: V/m). Sometimes the field on the electrode needs to exceed a certain quantity in order for a sustained discharge to occur. If that is not the case in a specific model, this setting can be ignored.
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Refinement factor. This factor determines how many particles are to be released per mesh element on the surface mesh. The default means that one particle will be released per surface mesh element. This value should not need to be changed except in rare cases, where the mesh is very coarse and there are obstructions between the cathode and grounded surfaces.
initial value of auxiliary dependent variables
If there are auxiliary dependent variables included, then this section will be populated with text fields to specify initial conditions for those variables.