Student majoring in engineering physics and EE gains hands-on experience in summer REU program

Whether he is simulating fusion experiments at Lehigh or studying biomedical technology, Chris MacDonald ‘05 seldom stops thinking about his younger sister.
Kim MacDonald was just 5 when she developed a malignant tumor in her neck. After many rounds of chemotherapy, the cancer recurred for a third time and doctors told the family there was little chance Kim would survive. Then, specialists at Johns Hopkins School of Medicine implanted a small device that released continuous doses of radiation into the center of the tumor. The experimental treatment shrank the tumor and saved Kim’s life.
Today, Kim MacDonald is a freshman at the University of Mary Washington in Virginia, and Chris has a deep appreciation for the power of medical technology.
“My sister survived because of the state-of-the-art treatment she received,” he says. “She’s alive thanks to the progress of medical technology.
“Because of that, I’d like eventually to get a Ph.D. in some field – engineering, physics, it doesn’t matter – that will prepare me to work in biomedical technology.”
MacDonald is enrolled in a dual-major program through the engineering college, working for a B.S. in engineering physics and a B.S. in electrical engineering. He is completing the five-year, 165-credit program in four years by taking 18-20 credits, including five or six technical classes, each semester. In his spare time, he plays trumpet in the Lehigh University Philharmonic and teaches SAT and MCAT courses.
After he graduates next spring, Chris hopes to spend a year at the University of Sydney in Australia developing and testing plasma-based technologies that could give rise to new biocompatible surface coatings and make heart valves and other medical implants cheaper and safer.
Chris got a head start studying plasma physics last summer when he was chosen to take part in the Research Experience for Undergraduates (REU) program run by Lehigh’s department of physics. The program, one of the longest-running REU programs in the U.S., has received funding since 1989 from the National Science Foundation, which recently renewed its commitment to the university for the next five years.
As an REU student, Chris ran computer simulations of physical experiments conducted inside a small nuclear fusion reactor located in San Diego at General Atomics, which is currently running the largest fusion experiment in the United States.
Nuclear fusion occurs when the nuclei of hydrogen isotopes fuse under extreme pressure and temperatures approacing 350 million degrees Celsius (hotter than the sun), creating heavier atoms, releasing large amounts of energy and producing harmless helium gas as a byproduct. Under the right conditions, the reaction becomes self-sustaining and produces energy continuously.
Unlike power plants that run on fossil fuels, fusion emits no pollutants or greenhouse gases. Unlike nuclear power plants, which rely on fission, or the splitting of atoms, fusion emits no plutonium or uranium waste. And it uses such a small amount of fuel that there is no danger of a leak on the scale of the deadly meltdown in Chernobyl, Ukraine.
MacDonald has worked closely with Glenn Bateman, research scientist in the physics department. Bateman and Arnold Kritz, professor of physics and leader of the Lehigh fusion research group, are two of the world’s leading fusion experts. They collaborate with researchers in Europe, Asia and North America, including scientists at General Atomics and at Princeton University’s Plasma Physics Laboratory.
The goal of Lehigh’s fusion group, says MacDonald, is to use computer simulation to predict, first, the results of actual fusion experiments, and, later, the results of physical tests on a scale too large to be done currently in a lab.
The Lehigh fusion group uses a simulation code known as ASTRA, or Automated System for Transport Analysis, which was developed by researchers in Russia and has been modified and expanded by researchers at Lehigh.
“Our computer model attempts to work hand in hand with the physical experiments that are being done inside the fusion reactor at General Atomics,” says MacDonald.
“Once we verify that our simulation codes accurately predict what happens in a physical experiment, the next step is to try to predict what would happen in a larger reactor. For example, what would happen in a reactor that is 10 times as large as the reactor at General Atomics? What would need to happen for the reactor to generate 10 times as much power?
“Simulations light the way to do new physical experiments. They save a lot of time and money; it’s much easier to simulate the behavior of a new reactor than to build a new one.”
In his work, MacDonald has focused on the edge of the donut-shaped fusion reactor, where the swirling plasma (ionized gas) formed by the hydrogen isotopes reaches its highest speeds.
“The edge confines everything,” says MacDonald. “The goal is to keep heat from escaping.”
During his REU internship, MacDonald attended a plasma physics conference for one week at Princeton, where he saw the National Spherical Torus Experiment (NSTX), an innovative magnetic fusion reactor at the Princeton Plasma Physics Laboratory.
At the end of the summer, MacDonald submitted a 30-page technical report to NSF. On Nov. 15, he will travel to Savannah, Ga., to give a poster presentation on his work to the 46th Annual Division of Plasma Physics Meeting of the American Physical Society.
“This has been a really exciting project. The REU program at Lehigh is really good; it allows you to do actual research. And the things I’ve learned as an electrical engineering major, from solid-state to signal processing, have been really helpful.
“I’m hoping one day that the skills I’ve acquired through the REU program and other programs will help me contribute towards the saving of someone else’s life, just as a researcher once helped save my sister’s life.”