The American Association for the Advancement of Science, the world’s largest general scientific society and publisher of the Science family of journals, has elected William Matthaeus, Unidel Professor of Physics and Astronomy at the University of Delaware and director of the Delaware Space Grant Consortium, to the 2022 class of AAAS Fellows — one of the most distinguished honors within the scientific community. 

Matthaeus is recognized “for outstanding contributions to the understanding of space and astrophysical plasmas through unique and innovative theoretical and observational insights, scholarship, research, teaching, mentoring and enabling other community members.”

Since he joined the UD faculty in 1983, Matthaeus has pioneered research on the heliosphere, the atmosphere around the sun, where temperatures can reach as high as 3.5 million degrees Fahrenheit. Specifically, he has made significant discoveries about the solar wind, which is made up of extremely hot electrically charged gas called plasma that shoots out from the sun at a million miles per hour, including its magnetic fields and turbulent flow. 

Solar wind drives energy throughout our solar system, and when it flows at particularly high and fluctuating velocities and collides with Earth’s magnetic field, it can disrupt satellites orbiting Earth and knock out power grids on land, among other impacts. 

“When I was a postdoc, people didn’t think there was any active turbulence in the solar wind,” Matthaeus said. “But I went to Goddard Space Center and started to look at data coming back from the Voyager mission. You could actually see the turbulence. Now 40 years later, the perspective I promoted as a postdoc is completely accepted. 

“If I’ve had a success in my career,” he added, “it’s the recognition that plasmas in the interplanetary medium are active and turbulent, and that points to the complication of the magnetic field. In turbulence, things are more like a messy head of hair instead of it being nicely coiffed.”

Matthaeus is currently co-investigator on multiple NASA missions studying the sun: the Parker Solar Probe, Magnetospheric Multiscale Mission, Interstellar Mapping and Acceleration Probe, Polarimeter to Unify the Corona and Heliosphere (PUNCH), HelioSwarm and Solar Orbiter (a joint mission with the European Space Agency), among them.

“We’ve maintained a very productive group for the past 40 years — it’s a lot to look back over, and also a lot to look forward to,” Matthaeus said. “It’s good to help young people along.”

Matthaeus has mentored dozens of UD students, many who are now succeeding famously in their own careers, ranging from university president to member of the U.S. National Academy of Sciences. He also has made an important impact on the research community internationally.

In 2018, he was awarded the Ruth Gall Award for Contributions to Latin American Science by ALAGE, the Latin American Association of Space Geophysics. 

When notified about the award, Matthaeus asked why it was being given to him. The answer came with a long list of people he had collaborated with, mentored, helped in some way.

He said he doesn’t have a magic formula for mentoring; he treats his students and faculty colleagues as friends.

“I think I tend to really interact with people as people,” Matthaeus said. “We’re not very formal here. If a student approaches me with “Professor Matthaeus,” I say, ‘No, call me Bill.’ My students know my door is always open. They don’t have to make appointments with me.”

Almost invariably people who work with Matthaeus become personal friends. One of his first doctoral students, who graduated from UD 30 years ago, still comes back to visit him every year. Other alums also visit regularly, even exchange students whom he taught from Thailand. 

He also promotes his students interacting with each other. As co-investigator on the Magnetosphere Multiscale (MMS) mission, he and his students decided to have an “MMS Festival,” where each student would contribute what they knew to a project. 

“Everybody got at least one first-author paper from that experience and it made the team gel,” Matthaeus said. “You have to have individual effort, but people tend to work harder when the person next to them is supportive.”

Matthaeus is author or co-author of more than 500 scientific publications. He also is a Fellow of the American Geophysical Union, American Physical Society, and the Institute of Physics. In 2019, he received the prestigious James Clerk Maxwell Prize for Plasma Physics.

Honoring esteemed innovators is a AAAS tradition dating back to 1874. Matthaeus is the 78th faculty member in UD history to be elected a AAAS Fellow.