American theoretical plasma physicist at the University of Wisconsin–Madison — a leading expert on MHD stability theory, neoclassical tearing modes, and stellarator optimisation.
ReviewedLast reviewed: 9 Aug 2026·Category: Scientists & Pioneers
Career
Christopher Hegna is a professor of engineering physics at the University of Wisconsin–Madison and a leading theorist in magnetohydrodynamic (MHD) stability and transport in toroidal plasmas. His work spans both tokamak and stellarator physics, with particular contributions to understanding neoclassical tearing modes (NTMs) and their stabilisation.[1]
NTM theory: Hegna’s theoretical framework for neoclassical tearing modes — magnetic islands sustained by a deficit in the bootstrap current — has been essential for predicting and controlling these performance-limiting instabilities in tokamaks. NTM stabilisation by localised electron cyclotron current drive, guided by Hegna’s theory, is now a standard technique.
Contributions
Beyond NTM theory, Hegna has made significant contributions to: stellarator MHD stability theory and optimisation criteria; resistive wall mode physics; and the theory of magnetic island evolution. He has been active in the Helically Symmetric Experiment (HSX) and contributed to the physics basis for Type One Energy’s stellarator reactor concept.[2]
Recognition
Hegna is a Fellow of the American Physical Society, Division of Plasma Physics. He has served as chair of the University Fusion Association and on DOE Fusion Energy Sciences Advisory Committee panels.[3]
Sources
Hegna, C.C. and Callen, J.D. "On the stabilization of neoclassical magnetohydrodynamic tearing modes using localized current drive or heating." Physics of Plasmas, 4, 2940, 1997.
University of Wisconsin-Madison. "Chris Hegna." engineering.wisc.edu.
American Physical Society. "APS Fellows: Christopher Hegna." aps.org.