NUCLEAR FUSION DEVICE UPDATED
“We have all these eager scientists that are waiting to ... learn more about how to make fusion work.” General Atomics’ powerful magnet part of research on making commercial fusion power plants a reality
After a shutdown of nearly six months for upgrades, a powerful magnetic chamber on the campus of San Diego’s General Atomics that is instrumental in the search to someday make nuclear fusion a practical source of energy is poised to restart operations.
The DIII-D National Fusion Facility at General Atomics fuses hydrogen atoms at extraordinarily high temperatures to recreate the power of the sun.
It’s done in a magnetic chamber called a tokamak, a doughnutshaped metal vacuum chamber surrounded by incredibly powerful magnets. Fuel consisting of hydrogen isotopes can be converted into plasma by heating the fuel to more than 180 million degrees Fahrenheit.
DIII-D, pronounced “dee-threedee,” is the largest tokamak in the United States.
“The sun is a hot ball of plasma,” said Richard Buttery, director of DIII-D. “The sun holds itself together with gravity because it’s got a lot of mass. We replace the mass with magnetic fields and we energize our coils, ramp it all up and we can contain the plasma.”
Supported by the U.S. Department of Energy, DIII-D periodically undergoes a “vent” period for maintenance and upgrades. Work was paused in July 2021 but operations are scheduled to restart on Friday with two notable improvements.
One is the installation of a Toroidal Field Reversing Switch, which allows the redirection of 120,000 amps of current that power the primary magnetic field. The upgrade will allow researchers to switch directions of the magnetic fields within minutes instead of hours. No other tokamak has the capability to switch the direction of the magnetic field so quickly, General Atomics researchers say.
Another upgrade is a travelingwave antenna that allows physicists to inject high-powered “helicon” radio waves into DIII-D plasmas so fusion reactions occur much more powerfully and efficiently.
“We’ve got new tools for flexibility and new tools to help us figure out how to make that fusion plasma