Like surfers catching ocean waves, particles within the hot, electrically charged state of matter known as plasma can ride waves that oscillate through the plasma during experiments to investigate the production of fusion energy. The oscillations can displace the particles so far that they escape from the doughnut-shaped tokamak that houses the experiments, cooling the plasma and making fusion reactions less efficient. Now a team of physicists led by the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) has devised a faster method to determine how much this interaction between particles and waves contributes to the efficiency loss in tokamaks.