# Electromagnetic fields

An electromagnetic field is a physical field produced by moving electrically charged objects. It affects the behaviour of charged objects in the vicinity of the field. The electromagnetic field extends indefinitely throughout space and describes the electromagnetic interaction. It is one of the four fundamental forces of nature (the others are gravitation, the weak interaction, and the strong interaction). The field can be viewed as the combination of an electric field and a magnetic field. The electric field is produced by stationary charges, and the magnetic field by moving charges (currents); these two are often described as the sources of the field. (Source)

flowL is a Grasshopper plug-in developed by Ursula Frick and Thomas Grabner from [uto], which visualises a vector field, generated through positive and negative point charges. The path lines are calculated with the ‘Runge-Kutta 4th Order Method’ or ‘RK4’ for short, developed by the German mathematicians C. Runge and M.W. Kutta around 1900.

To create a 2D vector field with 4 points:

To create a 3D vector field with 4 points: