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PHYS4201/4202 - Electricity & Magnetism



          DESCRIPTION: This code plots electrostatic field lines for a collection of point charges.

          MAIN GOAL: To draw the field lines in such a way that their volume density is proportional to the electric flux
                              penetrating any finite surface area.

          MAIN IDEA: Start field lines very close from a given charge. Then, if the initial points are distributed
                             *uniformly* over a tiny sphere surrounding the charge, the propagated lines will
                             automatically "adjust" themselves in space with correct volume density.
                            
          MAIN PROBLEM: In general, it is impossible to *uniformly* distribute an arbitrary number M of points
                                   on the surface of a sphere. That can only be done for M = 4, 6, 8, 12, and 20,
                                   which correspond to the number of vertices of the so-called Platonic solids.

          NOTE 1: Thus, in our implementation of the code, the number of field lines originating on a given
                       charge is proportional to the charge and equal to the number of vertices of the corresponding
                       Platonic solid. Due to this restriction, only charges q = 1, 1.5, 2, 3, 5, -1, -1.5, -2, -3, -5,
                       may be used.

          NOTE 2: If net charge is *positive* (or *zero*), only field lines originating on *positive* charges are
                       propagated. In this case, propagation direction is *forward*.

                       If net charge is *negative*, only field lines originating on *negative* charges are propagated.
                       In this case, propagation direction is *backward*.

          NOTE 3: *Position vectors* should be entered as [1 -3 5], or [1, -3, 5], etc. Make sure that the charges
                       are "reasonably well" localized.

          YOU HAVE TO SPECIFY:

                       Number of positive charges;
                       Positive charges;
                       Locations of positive charges;
                       Number of negative charges;
                       Negative charges;
                       Locations of negative charges;

         YOU MAY WANT TO START WITH A SIMPLE SYSTEM, say, a dipole with 1 positive charge +5
                       located at [0 0 0] and 1 negative charge -5 located at [0 0 1].




The Founding Fathers of Electrodynamics:

   

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