Steffi Diem

Plasma Physicist | Fusion Engineer | Technology Leader

Building the science, technology, and systems needed to move fusion energy from the laboratory to the world

I’m an experimental plasma physicist and fusion engineering working at the intersection of fusion science, technology development, and deployment. At the University of Wisconsin-Madison, I lead the Pegasus-III Experiment, bringing together researchers, engineers, students and collaborators to advance plasma science to develop technologies aimed at reducing the cost and complexity of future energy systems. I also founded the Fusion Impacts Collaborative, an interdisciplinary effort that connects expertise across engineering, economics, environmental science, policy, and societal sciences to better understand the broader systems that will shape how fusion is developed and deployed.

My work has taken me from national laboratories and experimental fusion facilities to the White House, Congress, and international science diplomacy. I was appointed as the first U.S. Science Envoy for fusion energy and work across academia, government, industry, and the public to help shape how fusion moves from scientific achievement to an energy technology at global scale.

2024/2025 U.S. Science Envoy

U.S. Department of State

Appointed by the Secretary of state as the first u.s. science envoy for fusion energy

2025 Kavli Fellow

National academies of science, engineering and medicine

New Voices of the National Academies

national academies of science, engineering and medicine

selected by the national academies for the 22 member cohort 2021 and to extend appointment to join cohort 2024, selected as co-chair

2023 David J. Rose Excellence in Fusion Engineering Award

fusion power associates (FPA)

selected by the FPA board of directors

Assistant Professor, Nuclear Engineering & Engineering Physics

University of wisconsin-madison

PI of Pegasus-III and the Just fusion collaborative

Ph.D. and M.A. in Astrophysical Sciences, Plasma Physics

Princeton University

Thomas H. Stix graduate prize

B.S. Nuclear Engineering & Engineering Physics, Physics

University of Wisconsin-Madison

Graduated with Highest Honors, Barry Goldwater Scholar

Additional Educational Training:

Alan Alda Science Communication Bootcamp at Stony Brook University

Women In STEM Leadership Program at Stony Brook University

Recent and Upcoming Events