Skip to main content

Research Success Story

Research Success Story

Plasma Stars

Star mode plasma by Brian Kelleher and Bill Flynn

Star mode plasma in fusor built by Brian Kelleher and Bill Flynn

When Bill Flynn and Brian Kelleher leave the McKinley basement lab for PhD programs this summer, they'll leave behind their Hirsch-Meeks fusor. Conceived by inventor Philo T. Farnsworth as an offshoot of vacuum tube experiments for his more famous 1930s creation, the TV, the fusor lets researchers like Flynn and Kelleher pursue high energy physics with less space and funding than your average particle accelerator typically requires.

But building and operating a fusor themselves presented significant challenges—and safety concerns. According to Flynn, electrons in the fusor reach temperatures of 100 million °C, and photons created are so energetic that lead shieldings must surround the device. To minimize risks, Flynn and Kelleher left aside the most dangerous scope of fusor experimentation—working with deuterium gas and neutron emissions—and limited themselves to creating and measuring plasma: in other words, the more mundane goal of superheating an electron soup that simulates conditions in a star.

The fusor may be the most salient achievement of Flynn's impressive AU career, which last year included a national Goldwater Scholarship and culminated in the 2010 University Award for Outstanding Scholarship at the Undergraduate Level. Given to only two graduating seniors each year, the award recognizes exemplary student scholarship reflected in research activity, merit awards, and contributions to the academic community outside AU. But Flynn credits Kelleher, BS physics '10, with dreaming up the project and proposing the collaboration. Says Kelleher, "I knew that I had the experimental abilities, but I was unsure about other challenges such as programming, data collecting, and, most of all, acquiring funds....His previous experiences at the National Institute of Standards and Technology (NIST) prepared him for programming, and his knowledge about honors grants and the honors department gave me confidence." 

Flynn and Kelleher received 2010 Honors Program Spring Grants to fund the project, and they shared the prize for Best Natural Sciences Paper at the College of Arts and Sciences' annual Mathias Student Research Conference. About the symbiosis they developed, Flynn notes, "I am the more theoretical, computational, methodical one, and Brian is the experimental, motivated ‘do-er.’ Brian will try 1000 different ways to overcome an obstacle, while I would spend my time just trying to think of the best one." Both benefited from the experience of previous collaborations: each has interned at NIST, and Flynn had worked with professors Nathan Harshman (physics) and Josh Lansky (mathematics and statistics) on applications of quantum information theory and with Phil Johnson (physics) on optical lattices.

Success with the fusor depended on continual support from physics chair UJ Sophia and lecturers Bill Parson and Jonathan Newport. As Kelleher recalls, a critical moment arose when the project required a Langmuir probe to measure the plasma: "After reading a few papers from the late sixties, we built our probe from scratch. Our advisor, Jonathan Newport, showed us the necessary techniques, but let us design and build it ourselves. It was a bold move, but it allowed us to learn to build something ourselves."

Ultimately, after programming virtual instrumentation in LabVIEW, Flynn and Kelleher were able to produce valid results for publication. But the fusor's most enduring value may be its departmental role. Says Flynn, "We planned on leaving it for students to experiment with, but Bill Parsons came up with the great idea of making it part of the advanced experimental course for physics majors." Flynn and Kelleher will help devise the lab work this summer before heading to grad school, the former to Rutgers and the latter to Wisconsin.

"We are thrilled with the fusor that Brian and Bill built. It will introduce our students to a number of fascinating technologies and concepts, including plasma physics, high vacuum devices, very high voltages, and ultra-high temperatures," says Parsons. "In addition, the fusor setup will enable our students to use top-of-the-line data acquisition systems such as LabVIEW. This kind of training will serve our students well, whether they go on to grad school or industry."