Rensselaer and Oak Ridge National Laboratory (ORNL) continue to move forward with their research into bubble fusion, a pioneering technique used to create thermonuclear fusion. Their findings were first reported in March 2002 in the prestigious Science magazine, and sparked considerable interest in the international scientific community.

The team is now at work under a new grant from the Defense Advanced Research Projects Agency (DARPA). They hope to be able to demonstrate an increase in fusion yield by next summer.

"There's been a very positive response," says Richard T. Lahey Jr. '64, Rensselaer's Edward E. Hood Professor of Engineering and the project's co-director. "Venture capitalists have approached us about the possibility of using this technology, and numerous research teams around the world are currently working to duplicate the ORNL/RPI team's results."

Lahey says calls continue to come in from the media and interested members of the scientific community. He recently presented the team's latest bubble fusion results at the annual meeting of the American Nuclear Society and at an international conference in Poland.

"If we can demonstrate that we can increase the neutron yield, which we fully expect to be able to do, we anticipate a number of agencies will launch significant research programs in this area of technology," Lahey says. "DARPA has already indicated they plan to do just this."

Fusion power holds great potential for solving the world's energy problems, and Lahey says it could eliminate many of the drawbacks currently associated with nuclear power. "Most of the radioactive waste and safety issues will go away," he says. "Bubble fusion appears to be a very significant discovery."

The innovative experimental approach does not involve more commonly used plasma confinement approaches, such as those using magnetic fields or lasers. In bubble fusion, cavitation bubbles form, and rapidly grow, when liquid inside an ultrasonic pressure field is struck with high-energy neutrons. When the bubbles subsequently implode, tremendous compression occurs, creating temperatures exceeding millions of degrees Kelvin. During these implosions, researchers measured nuclear emissions, light flashes, and tritium production, which indicated that deuterium atoms had fused in the highly compressed bubbles. The reaction occurred in just a few trillionths of a second, with peak temperatures at least 1,000 times hotter than the sun's surface.

Lahey says the team has duplicated its experiment many times, and numerous experts in the field carefully reviewed the data before the March announcement.

Rusi Taleyarkhan '78 (ORNL project director), Colin West, and Jae Seon Cho performed the experiments at ORNL; Rensselaer Professor Robert Block helped set up and interpret the nuclear instrumentation and measurements. Lahey, a member of the National Academy of Engineering (NAE), and Robert Nigmatulin, a member of the Russian Duma and Academy of Science, performed theoretical analyses, predicted the observed phenomenon, and explained the data trends.

Originally published in School of Engineering News, Fall 2002

Published September 1, 2002