The U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) has been named principal investigator for a multi-institutional project to study plasma-materials interaction (PMI)on the Experimental Advanced Superconducting Tokamak (EAST) in China. The centerpiece of the PPPL role in this project is the optimization of lithium delivery systems. The tests will be designed to optimize the production of long-pulse plasmas that last from 30 seconds to more than one minute. This project is supported by Fusion Energy Sciences in the DOE Office of Science.
Physicist Rajesh Maingi (Credit: Elle Starkman/PPPL Office of Communications)
The three-year, approximately $2.1 million contract — subject to annual budget availability — is synergistic with other PPPL collaborations funded by DOE to investigate long-duration plasma confinement. These collaborations involve EAST, the Korean Superconducting Advanced Research (KSTAR) tokamak, and the Wendelstein-7X (W-7X) stellarator in Germany.
For the PMI project, PPPL will use devices called flowing liquid lithium limiters and granule injectors, as well as optimization of coating techniques, to protect the plasma-facing components inside the EAST facility. PPPL has applied lithium to its National Spherical Torus Experiment (NSTX), which has recently been upgraded, and will continue to use lithium. Also housed at PPPL is the Lithium Tokamak Experiment (LTX), a small, short-pulse complementary experiment that explores the effect of a liquid-lithium boundary on the plasma.
The new experiments will test the ability of lithium to protect the EAST walls and prevent impurities from bouncing back into the core of the plasma and halting fusion reactions. Success of such efforts could point to a method for optimizing long-running plasmas. “We’re trying to make a cohesive program so the things that we’ve learned in this country can be tried over there,” said physicist Rajesh Maingi, who will lead the PPPL effort. “Then we can bring back what we learn there to help us here.”
Collaborating with PPPL on the PMI project are the Los Alamos and Oak Ridge national laboratories, together with Johns Hopkins University, the Massachusetts Institute of Technology, the University of Illinois and the University of Tennessee.
PPPL, on Princeton University's Forrestal Campus in Plainsboro, N.J., is devoted to creating new knowledge about the physics of plasmas — ultra-hot, charged gases — and to developing practical solutions for the creation of fusion energy. Results of PPPL research have ranged from a portable nuclear materials detector for anti-terrorist use to universally employed computer codes for analyzing and predicting the outcome of fusion experiments. The Laboratory is managed by the University for the U.S. Department of Energy’s Office of Science, which is the largest single supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time.