In 1999, Tom Donnelly bought a cologne bottle and teamed with students to assess its fine-spray capabilities. The effort initiated a long-term program enabling HMC undergraduates to enter the world of laser-driven fusion, where solutions to domestic energy shortages and even global warming may someday be found.

“When you burn fossil fuels, you heat the planet,” said Donnelly, professor of physics. “Fusion doesn’t release any greenhouse gases.” Laser-driven fusion involves short-pulse lasers that are focused to create intense power that spikes during those brief laser bursts. When that power is used to slam together the nuclei of two deuterium atoms within water droplets far smaller than those emitted by that early cologne bottle, fusion—a form of energy—is created.

“If we could make a power plant based on fusion, then we could go to the oceans, fill buckets, remove the deuterium and power our plants,” said Donnelly. “That would provide a sustainable energy source for billions of years.”

Unfortunately, that is not yet possible. Enter Donnelly’s physics students, who are using increasingly smaller water droplets to investigate potential fusion applications. While he admits that the future of fusion may be decades away, he believes there is merit in studying fusion as an undergraduate—even though students will eventually pass their work on to another generation of HMC researchers.

“It goes to our mission statement: educating people who will lead in their fields and who understand the impact of their work on society,” Donnelly said. “I feel strongly that fusion is a research topic that can significantly contribute toward improving society in terms of leading the way to developing clean and sustainable alternate energy sources.”

Fusion is discussed in at least two of Donnelly’s classes: Modern Physics, and Electricity and Magnetism. However, excitement peaks in the lab, where students participate in various research projects and have an opportunity to use one of the world’s most powerful lasers. Such research is something few undergraduates in the country are able to experience.

“If there’s another group of undergraduates anywhere doing laser-driven fusion research in the lab, I don’t know about it,” Donnelly said. “It requires access to a major facility. I have a friend at the University of Texas, Austin, who built the most powerful laser in the world, and we have the privilege of working with his laser systems.”

There also is a laser in the W.M. Keck Laboratories, where students can puff a special aerosol vapor into a vacuum chamber, heat it with the laser and study the effects. One student project, titled Production of Harmonic Faraday Excitation with Applications in Laser-driven Fusion, by Andrew Higginbotham ’09 (physics), involved the development of methodology to create an aerosol composed of still-smaller particles in order to improve fusion yield. A second, by Ian Wright ’09 (physics), involved controlling the size of medically relevant particles for possible use as a vehicle in drug delivery and gene therapy.

“I look at what we’re doing as contributing to the body of knowledge of laser fusion,” said Higginbotham, who pointed to improved medical imaging as another potential fusion application. “Just getting to do real science as an undergraduate is great. And using high-intensity lasers is awesome.”

Donnelly went a step further. “These are not trivial experiments. This involves hard work.

“I’m not intimating that what we do will end up being a power plant. But thinking hard about problems that have longtime scale durations is something we can do in academics. If I can train students to work in a field that may have some longer term impact on the energy independence of this country, or help us take better care of the planet, then it’s time well spent.”