Press Releases Archive
Machine learning, which lets researchers determine if two processes are causally linked without revealing how, could help stabilize the plasma within doughnut-shaped fusion devices known as tokamaks. Such learning can facilitate the avoidance of disruptions — off-normal events in tokamak plasmas that can lead to very fast loss of the stored thermal and magnetic energies and threaten the integrity of the machine.
Throughout the universe, supersonic shock waves propel cosmic rays and supernova particles to velocities near the speed of light. The most high-energy of these astrophysical shocks occur too far outside the solar system to be studied in detail and have long puzzled astrophysicists. Shocks closer to Earth can be detected by spacecraft, but they fly by too quickly to probe a wave’s formation.
Opening the door to new understanding
Two major issues confronting magnetic-confinement fusion energy are enabling the walls of devices that house fusion reactions to survive bombardment by energetic particles, and improving confinement of the plasma required for the reactions. At the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL), researchers have found that coating tokamak walls with lithium— a light, silvery metal— can lead to progress on both fronts.
For fusion to generate substantial energy, the ultra-hot plasma that fuels fusion reactions must remain stable and kept from cooling. Researchers have recently shown lithium, a soft, silver-white metal, to be effective in both respects during path-setting U.S.-Chinese experiments on the Experimental Advanced Superconducting Tokamak (EAST) in Hefei, China. Leading the U.S. collaboration is the U.S.
A nationwide team of researchers led by physicist C.S. Chang of the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) has won the use of 269.9 million supercomputer hours to complete an extreme-scale study of the complex edge region of fusion plasmas. The award was made by the DOE’s ASCR Leadership Computing Challenge (ALCC) program for 2017, supported by DOE’s Office of Science.
Lithium compounds improve plasma performance in fusion devices just as well as pure lithium does, a team of physicists at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) has found.
Physicists at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) have simulated the spontaneous transition of turbulence at the edge of a fusion plasma to the high-confinement mode (H-mode) that sustains fusion reactions. The detailed simulation is the first basic physics, or first-principles-based, modeling with few simplifying assumptions.
Physicists at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) have helped develop a new computer model of plasma stability in doughnut-shaped fusion machines known as tokamaks. The new model incorporates recent findings gathered from related research efforts and simplifies the physics involved so computers can process the program more quickly. The model could help scientists predict when a plasma might become unstable and then avoid the underlying conditions.
Everyone knows that the game of billiards involves balls careening off the sides of a pool table — but few people may know that the same principle applies to fusion reactions. How charged particles like electrons and atomic nuclei that make up plasma interact with the walls of doughnut-shaped devices known as tokamaks helps determine how efficiently fusion reactions occur. Specifically, in a phenomenon known as secondary electron emission (SEE), electrons strike the surface of the wall, causing other electrons to be emitted.
Researchers at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) and General Atomics have simulated a mysterious self-organized flow of the superhot plasma that fuels fusion reactions. The findings show that pumping more heat into the core of the plasma can drive instabilities that create plasma rotation inside the doughnut-shaped tokamak that houses the hot charged gas. This rotation may be used to improve the stability and performance of fusion devices.
Magnetic reconnection, a universal process that triggers solar flares and northern lights and can disrupt cell phone service and fusion experiments, occurs much faster than theory says that it should. Now researchers at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) and Germany’s Max Planck Institute of Plasma Physics have discovered a source of the speed-up in a common form of reconnection. Their findings could lead to more accurate predictions of damaging space weather and improved fusion experiments.
Like a potter shaping clay as it spins on a wheel, physicists use magnetic fields and powerful particle beams to control and shape the plasma as it twists and turns through a fusion device. Now a physicist has created a new system that will let scientists control the energy and rotation of plasma in real time in a doughnut-shaped machine known as a tokamak.
U.S. Department of Energy (DOE) high-performance computer sites have selected a dynamic fusion code, led by physicist C.S. Chang of the DOE’s Princeton Plasma Physics Laboratory (PPPL), for optimization on three powerful new supercomputers. The PPPL-led code was one of only three codes out of more than 30 science and engineering programs selected to participate in Early Science programs on all three new supercomputers, which will serve as forerunners for even more powerful exascale machines that are to begin operating in the United States in the early 2020s.
Physicist Igor Kaganovich at the Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) and collaborators have uncovered some of the physics that make possible the etching of silicon computer chips, which power cell phones, computers, and a huge range of electronic devices. Specifically, the team found how electrically charged gas known as plasma makes the etching process more effective than it would otherwise be.
Physicist Fatima Ebrahimi at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) has published a paper showing that magnetic reconnection — the process in which magnetic field lines snap together and release energy — can be triggered by motion in nearby magnetic fields. By running computer simulations, Ebrahimi gathered evidence indicating that the wiggling of atomic particles and magnetic fields within electrically charged gas known as plasma can spark the onset of reconnection, a process that, when it occurs on the sun, can spew plasma into space.
Physicists at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) have for the first time directly observed a phenomenon that had previously only been hypothesized to exist. The phenomenon, plasmoid instabilities that occur during collisional magnetic reconnection, had until this year only been observed indirectly using remote-sensing technology.
The past year saw many firsts in experimental and theoretical research at the U.S. Department of Energy’s Princeton Plasma Physics Laboratory (PPPL). Here, in no particular order, are 10 of the Laboratory’s top findings in 2016, from the first results on the National Spherical Torus Experiment-Upgrade to a new use for Einstein’s theory of special relativity to modeling the disk that feeds the supermassive black hole at the center of our galaxy.
1. First results of the National Spherical Torus Experiment-Upgrade (NSTX-U)
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