Set desiredPotentialValue = 400.0
Set potentialSurfaceGrid = 50
For an isolated charge, the equipotential surfaces are spheres centred at the charge. A general result is that field lines are orthogonal to equipotencial surfaces.
Rotate the cube to get a 3-D view of the system charge + equipotential surfaces.
The introduction of the electric potential, that can be easily justified in Electrostatics since the static E field is conservative, allows a description of electrostatic phenomena in terms of a scalar field. This description is mathematically simpler and, at the same time equivalent to the description in terms of the vector electric field (which has been used in the previous simulation through visualization of the force lines).
In both cases, space is "labelled" at each point with the value of a vector or a scalar, respectively.