A torus of plasma, viewed from above. The ring is created by a jet of water striking a crystal plate.
For the first time, Professor Morteza Gharib and colleagues have created a stable ring of plasma in open air using just a stream of water and a crystal plate. The team fired the water jet at surfaces of different textures and found that the smoother the surface, the clearer the structure of the plasma ring. The ring is stable, and as long as the water continues to flow, the ring maintains its shape and size. [Caltech story]