Ordinary experimental fluids are subject to effects like viscosity and can be difficult to manipulate. Durkin and Fajans therefore used a cylindrical column of magnetically confined electrons to simulate a perfect fluid. Electron density is equivalent to fluid vorticity, and this strongly magnetized electron column behaved as a vortex. The researchers used a photocathode to produce a region of high electron density - or vortex - in the cylinder of electrons.

The intense point-like vortex traced a circular clockwise path, spinning in the same direction as the larger vortex. As the small vortex circulates, it causes a wave to form on the perimeter of the larger vortex. The wave grows and produces a trailing filament. After several revolutions of the large disc, the filament rejoins the main body of the vortex, enclosing a "vorticity hole" which becomes incorporated into the weaker disc. The hole acts like a vortex spinning in the opposite direction. As it is pulled further into the disc by the point-like vortex, the motion of the whole system becomes chaotic.

Durkin and Fajans also experimented with other configurations. The pair introduced seven randomly placed intense vortices into a weaker vortex. The same phenomenon took place, but surprisingly, the vortices arranged themselves into the shape of a regular hexagon with one central vortex - a process known as crystallization.

"What still amazes me is how well three-dimensional electron columns model two-dimensional fluids", Durkin told PhysicsWeb. "The columns are essentially analogue computers that model 2D flows, and our ultimate goal is to simulate a planet's atmosphere."