Princeton University astrophysicist Amitava Bhattacharjee is set to lead an international team as it works to create a framework for an optimal fusion energy device.
The team, which is putting forth the effort to replicate on Earth the fusion reactions that power the sun and stars to produce a virtually limitless supply of electricity, won a Simons Foundation Mathematical and Physical Sciences Award valued at $2 million a year for four years to create the framework for an optimum stellarator that combines the best features of both types of fusion reactors, the university said in a news release.
“I cannot tell you how excited I am,” said Bhattacharjee, an Indian American professor of astrophysical sciences at Princeton who directs the international collaboration. “This project requires fundamental breakthroughs in physics, mathematics and computation. If successful, we will be able to design the world’s best fusion reactor with importance for the entire world.”
The sun and stars produce fusion by crushing together light elements in the form of plasma — the hot, charged state of matter composed of free electrons and atomic nuclei — with powerful gravity, the university said.
Here on Earth, stellarators and tokamaks use magnetic fields in lieu of gravity to confine and control the plasma, and temperatures hotter than the core of the sun to fuse the nuclei to release their energy, it said.
Stellarators — first proposed in the early 1950s – took a back seat a decade later to tokamaks invented in the former Soviet Union, which proved better able to confine plasma and were easier to design and build, the university said.
But stellarators are now making a comeback, with major ones operating in Germany and Japan thanks to the computational capability of supercomputers and breakthroughs in mathematical techniques and physics understanding, it added.
A key feature of stellarators is their ability to operate without the electrical current that tokamaks must induce in plasma to complete the magnetic field. Such current poses a risk for tokamaks since instabilities in the plasma can cause the release of energy stored in the current, producing disruptions that can halt fusion reactions and damage tokamak components, the news release said.
An optimum stellarator would therefore combine the tokamak’s superior ability to confine the plasma with the stellarator’s ability to operate in a steady state without plasma current, it said.
The twisty magnetic fields of an optimum stellarator would have “hidden symmetries” that confine plasma in a manner comparable to the smooth, round — or “axisymmetric” — fields that tokamaks produce, it added.
This enormously complex project, titled “Hidden Symmetries and Fusion Energy,” will require many breakthroughs, the report said.
The diverse group, assembled from eight U.S. universities and four international institutions, will create a code called SIMSOPT — for SIMonS OPTimization code — to produce the framework for an optimum stellarator design, the university added.
Collaborators are from Princeton, Columbia, Cornell and New York University, and from the University of Colorado-Boulder, the University of Maryland, and the University of Texas at Austin. International participants represent the Australian National University, the University of Warwick, the Swiss École Polytechnique Fédérale de Lausanne and the Max Planck Institute for Plasma Physics in Germany.
“Our team reflects a breadth of enterprise with mathematicians and computational experts who don’t necessarily have a lot to do with plasma physics,” Bhattacharjee said in the report. “But these are experts who can provide breakthroughs and we are grateful to the Simons Foundation for this great opportunity.”
