Computers model frozen fuel in blazing fusion reactor
Posted June 4, 2007
Plasma image following injection of a frozen deuterium pellet.Credit: TFTR Project, PPPL |
Ravi Samtaney’s work is a study in extremes.
His computer codes simulate what happens when pellets of hydrogen isotopes frozen to near absolute zero are shot into a plasma cloud more than six times hotter than the sun’s interior.
The hydrogen pellets are smaller than pencil erasers. The chamber they enter may be two or three stories tall.
The pellets vaporize in milliseconds; yet Samtaney, a researcher at the Department of Energy’s Princeton Plasma Physics Laboratory, must break the process into hundreds of steps.
The simulation is important for nuclear fusion – the process behind the sun’s power and a possible source of abundant, clean energy on earth.
A fusion reactor that produces more energy than it consumes is the goal of ITER, a collaboration between the United States and several other countries. ITER, to be built in France, will house a five-story-tall torus, or donut-shaped chamber, called a tokamak.
Powerful magnetic fields will hold the fiery plasma in the torus. The high temperature will strip electrons from the hydrogen atoms and the resulting charged particles will spin through the circular cavity, fusing and releasing energy.
Samtaney’s codes simulate refueling – the injection of frozen hydrogen isotope pellets to keep the reaction going. (Different isotopes of an element have the same number of protons, but different numbers of neutrons, in their nucleus.)
