Cary Forest is the Prager Professor of Experimental Physics at the University of Wisconsin–Madison and Director of the Wisconsin Plasma Physics Laboratory. His research sits at the intersection of fusion energy, plasma physics, and laboratory plasma astrophysics, with a particular emphasis on building new experimental platforms that make difficult plasma phenomena measurable.
Forest is a machine builder—a distinction that has shaped his career. Over the past three decades, he and his collaborators have conceived, designed, and operated a sequence of major plasma experiments, including early spherical tokamaks, reversed-field-pinch plasmas, liquid-metal dynamos, line-tied reconnection experiments, plasma Couette flow devices, the Big Red Ball, and the Wisconsin HTS Axisymmetric Mirror. These machines have been used to study magnetic self-organization, plasma heating and current drive, turbulent dynamos, magnetic reconnection, shocks, stochastic transport, plasma flows, and compact high-field approaches to fusion.
His current work focuses on WHAM, the Wisconsin HTS Axisymmetric Mirror, a high-field magnetic mirror experiment built around high-temperature-superconducting magnet technology. WHAM is part of a renewed effort to understand whether compact, high-field mirrors can provide a practical route to fusion neutron sources and, ultimately, fusion energy. Forest also co-founded Realta Fusion, a company developing compact mirror-based systems for fusion energy and fusion neutron applications.
Forest’s research philosophy is simple: build the machine needed to see the physics clearly. His group combines hands-on experimental design, diagnostic development, theory, computation, and close collaboration with students, national laboratories, and industry.
Research
Forest’s research program combines fusion energy science with laboratory plasma astrophysics. A central theme is the construction of purpose-built plasma experiments that can isolate and test the physics of magnetic fields, flows, waves, turbulence, energetic particles, and plasma-material interactions.
Current work centers on high-field magnetic mirror confinement through WHAM. Using modern high-temperature-superconducting magnets, strong plasma heating, neutral beam injection, and long-pulse operation, WHAM explores whether the magnetic mirror can be reopened as a practical fusion concept. This effort connects university-scale plasma science with the development path for compact fusion neutron sources and future fusion energy systems.
A second major thrust is the Wisconsin Plasma Physics Laboratory, a collaborative experimental facility that brings together large plasma devices for studies of energy conversion in plasmas. Experiments in WiPPL address magnetic reconnection, turbulent dynamos, shock formation, plasma flows, particle acceleration, and the transfer of energy between magnetic fields, flow, heat, and particles.
Forest’s earlier work includes contributions to spherical tokamak formation, non-inductive current drive, electron Bernstein wave heating, stochastic magnetic-field transport in reversed-field-pinch plasmas, liquid sodium dynamos, line-tied kink stability, plasma Couette flow, and the laboratory creation of solar-wind-like magnetic structures in the Big Red Ball.
Selected Research Themes
High-field mirror fusion
Forest leads research on WHAM, the Wisconsin HTS Axisymmetric Mirror, which explores compact mirror confinement using modern high-field superconducting magnet technology.
Fusion translation
Forest co-founded Realta Fusion to help move high-field mirror concepts from university research toward practical fusion neutron and energy applications.
Laboratory plasma astrophysics
Forest’s group has built experiments to study dynamos, magnetic reconnection, plasma flows, collisionless shocks, and solar-wind-like magnetic structures in the laboratory.
Plasma heating and current drive
His work has contributed to spherical tokamak startup, advanced tokamak performance, non-inductive current drive, and electron Bernstein wave heating in overdense plasmas.
Plasma-material and liquid-metal technologies
Recent work includes liquid-metal concepts for high-field fusion systems, including in situ electromagnetic pumping approaches relevant to fusion blankets and plasma-facing components.
Mentorship and community leadership
Forest has mentored a large cohort of students and postdoctoral researchers who now lead plasma programs across universities, national laboratories, and private fusion companies. He has also served in major leadership roles in the plasma physics community, including as Chair of the APS Division of Plasma Physics.
Biographical Sketch
Cary B. Forest received his B.S. from the University of Wisconsin–Madison in Applied Mathematics, Engineering and Physics and his Ph.D. from Princeton University’s Program in Plasma Physics. His doctoral work helped establish non-inductive startup techniques for spherical tokamaks and was recognized with the APS Simon Ramo Award.
After working at General Atomics on advanced tokamak physics, heating, current drive, and non-inductive current-profile measurements, Forest joined the faculty at the University of Wisconsin–Madison. At Wisconsin, his group has built and led a series of experimental plasma platforms, including liquid-metal dynamo experiments, line-tied pinch experiments, plasma Couette flow devices, the Big Red Ball, and WHAM.
Forest is a Fellow of the American Physical Society and has served in leadership roles across the plasma physics community. His work is unified by a blend of experimental craftsmanship, physical intuition, theoretical modeling, and a willingness to build new machines when existing ones cannot answer the question.