[bs] Electric Dipole

The Field lines and the equipotential surfaces. The potential surfaces of the dipole are rotationally symmetric about the p-axis. The potential become (+ inf) at the position of the positive charge and (- inf) at the position of the negative charge.

Classical Electrodynamics, Greiner, p.26.

E/p= - grad ( cos A / r^2 )

Matlab code :

[X,Z] = meshgrid(-0.8:.1:0.8,-1.2:.2:1.2);
U = Z./(X.^2+Z.^2);
[DX,DZ] = gradient(-U,.01,.01);
contour(X,Z,U)
hold on
quiver(X,Z,DX,DZ)
colormap hsv
hold off