E-Mail IMAGE: Physicist C.S. Chang with figure showing turbulence eddies in an ITER plasma edge (green) with the heat-load footprint on the material wall carried by escaping hot plasma particles. Model simulated... view more Credit: Photo by Elle Starkman/PPPL Office of Communications. Simulation and image from Robert Hager and Seung-Hoe Ku. Efforts to duplicate on Earth the fusion reactions that power the sun and stars for unlimited energy must contend with extreme heat-load density that can damage the doughnut-shaped fusion facilities called tokamaks, the most widely used laboratory facilities that house fusion reactions, and shut them down. These loads flow against the walls of what are called divertor plates that extract waste heat from the tokamaks.