The interior of this 18" x 18" x 1" piece of Plexiglas was charged to about 2.2 million volts (MV) by bombarding it with electrons from a 5 million electron volt (MeV) particle accelerator. This traps a layer of excess negative charge about half way through the specimen. When we manually discharge it, the trapped electrons escape with a brilliant flash and a loud bang. The hot, lightning-like discharges create thousands of microscopic channels and fractures inside the acrylic. The result is a branching "Captured Lightning" sculpture (or Lichtenberg Figure). This fractal 2D form has a fractal dimension of about 1.7.
This video was captured and edited by Terry Blake. The specimen was owned and discharged by Jeff Larson during our 2005 production run. Be sure to see our other videos about making Lichtenberg Figures: