John Sheffield

Dr. John Sheffield, 89, of Woodstock, Georgia, passed away peacefully on July 22, 2026. John Sheffield was a distinguished British-born physicist whose career was dedicated to plasma physics and fusion energy science. He is best known for his leadership roles in major international fusion projects and for his foundational work in plasma diagnostics. John was born on December 15, 1936, in London, England. He received a BSc in Physics from Imperial College London in 1958, and an MSc (1962) and PhD (1966) in Physics from the University of London.

John Sheffield’s fusion career began in 1958 at the Harwell and Culham Laboratories in England. In 1966, he joined the Fusion Research Center at the University of Texas before returning to Culham in 1971 to work on the design team for the Joint European Torus (JET) experiment. In 1977, he joined the fusion division at Oak Ridge National Laboratory (ORNL), serving as division head from 1988 to 1994. His leadership helped advance tokamak physics, plasma diagnostics, and heating techniques, including RF-assisted startup, pellet fueling, and improved impurity control.

From 1987 to 2003, he also served as Director for Energy Programs at ORNL and Executive Director of the Joint Institute for Energy and Environment, a joint institute between ORNL and the University of Tennessee. From 2003, he was a Senior Fellow at the Institute for a Secure and Sustainable Environment (formerly JIEE) at UT Knoxville. His particular interests were world population growth and future energy demand and resources; the opportunities for fusion energy, including options to enhance its attractiveness; and the connection between energy use and the environment.

John is a Fellow of the American Physical Society and the American Nuclear Society. In the 1990s, he served as a U.S. representative on committees that defined and then gave technical advice to the International Thermonuclear Experimental Reactor (ITER). He served as chair of the U.S. Department of Energy's Fusion Energy Sciences Advisory Committee (1996-2000) and received the Fusion Power Associates 1993 Leadership Award and the 2003 Distinguished Career Award. He also served on the Fusion Power Associates Board of Directors.

He is the author of the seminal work “Plasma Scattering of Electromagnetic Radiation”, widely regarded as the definitive reference on the subject. In addition to numerous technical works, John Sheffield also wrote other works including: Fun in Fusion Research, Marienna’s Fantasy, and Roseland’s Secret. He is a member of the Atlanta Writers Club, where he has won two first-place awards for poetry. He was also the recipient of the Southeastern Writers Association’s 2015 Edna Sampson Award for his humorous novel, My Friend Albert.

In his free time, John loved traveling and taking in unadoptable pets, like Spot, a 95-lb blind pit bull. John and “Spotty” formed an unbreakable bond and could be seen walking the streets of Woodstock. However, it was not always apparent who was walking whom.

He is survived by his wife, Sharon Curfman Sheffield, his two children from his first marriage, Jason and Nicholas, and his grandchild, Gabriel. He is also survived by his stepdaughters, Shanna and Lauren, his step-grandchildren, Hunter and Makenna, and his rescue animals, Georgie and Rocketman (dogs), and Katie, Molly, and Moonpie (cats). His first wife, Dace Kancbergs, predeceased him.

To honor John’s lifelong love for animals, the family welcomes memorial contributions in place of flowers to the Cherokee Animal Shelter. Please direct gifts to: https://www.cherokeega-animals.org/donate.