PPPL Physicist Roscoe White (IMAGE) DOE/Princeton Plasma Physics Laboratory Caption PPPL physicist Roscoe White and colleagues have furthered understanding of a barrier that can prevent doughnut-shaped fusion facilities known as tokamaks from operating at high efficiency by causing vital heat to be lost from them. Credit Elle Starkman / PPPL Office of Communications Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.