By Huck Fairman
For more than 60 years, scientists at Princeton University’s Plasma Physics Laboratory, as well as around the world, have looked at our Sun’s, and the stars’, processes for creating energy. This June at the university, the 23rd International PSI (Plasma Surface Interactions) Conference convened to share information and progress on harnessing the Sun’s fusion energy among more than 400 scientists.
If this globally collaborative effort to produce clean, unlimited energy succeeds in time – before global warming possibly changes our planet irreversibly – civilization may find that it can produce the increasing, clean energy it needs.
Our local university is involved in a number of different approaches that are and will produce efficient, clean energy, but the work at the Princeton Plasma Physics Laboratory (PPPL), which is operated for the U.S. Department of Energy, is perhaps science’s biggest bet. As examples shine and wink at us from throughout the universe, plasma physics is working to find ways to reproduce and contain the stars’ fusion energy. (Those stars and our Sun are fueled by the fusion of Hydrogen, creating light in the form of gamma rays which are largely trapped in the Sun, save for what escapes and we see as sunlight.) Success in this endeavor may save us; falling short could leave us unable to develop the energy changes we need.
Fusion is the process by which the sun and stars produce their energy – their heat and light. More specifically, fusion refers to the fusing of atomic nuclei, or ions, within a plasma, (sometimes called the fourth state of matter.) Plasma is a hot, electrically charged gas in which fusing can take place, thereby producing bursts of energy that may be used by mankind to generate electricity. If science can reproduce and contain this fusing, it will have produced the hopeful “star in a jar.”
But challenges remain.
First, PPPL is researching how to create this natural process on Earth, and under control. The plasma must be heated to tens of millions of degrees Celsius while also containing it within powerful magnetic fields. But again, if that energy can be controllably released, it could be used to generate electricity.
PPPL has just upgraded its major fusion facility (NSTX-U) to make it the most powerful fusion facility (or spherical torus, ST), in the world. Its new design, which is more compact, enables it to contain the highly pressurized plasma within weaker magnetic fields, which are more cost effective. But, at the same time, questions about the stability of the plasma core and about its behavior at the edge of confinement remain to be answered.
To pursue these and other questions, PPPL is collaborating with France’s huge new facility, ITER (under construction), and with other fusion facilities in China, South Korea and Germany. And just as this collaboration is international, so are PPPL’s faculty and staff, with members coming from around the world. Among its many contributors, Rajesh Maingi, head of boundary physics at Princeton, is this conference’s chair. Charles Skinner, originally from the U.K., and principal research physicist, is the Chair LOC. Egemen Kolemen, assistant Professor in the Dept. of Mechanical and Aerospace Engineering, grew up in Turkey and is the conference’s Princeton University’s representative.
Whether or not many recognize it, the future well being of our community of nations depends, in part, on the development of energy that does not dangerously change the environments that support us. The fact that scientists have been pursuing this goal for over sixty years is an indication of its importance. Even as it details the complexity of challenges ahead, this year’s 23rd PSI Conference at Princeton offers a number of hopeful progress reports and developments.