Dug out my old iterated function system generator to make a new logo for the site. Some of the other results are in this gallery:
http://arklyffe.com/gallery/v/cg/chargetraces/

These are simply images of a large number of particle trajectories in a "lumpy" force landscape. In a simple example:
http://arklyffe.com/gallery/v/cg/chargetraces/spark.jpg.html

The particles are repelled from their origin point by an inverse square force (with a softening factor to reduce the spike at the origin: graph) and flow through a landscape derived from a smooth noise function:

The result is analogous to electrons flowing from a point source through a slightly uneven environment. Though only individual particles trajectories are traced, and the "electrons" thus can not interact with each other, they form into distinct streams.