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Greg Wallace
Principal Research Scientist
Biography

Dr. Wallace is a leading expert in the physics and technology of radio frequency (RF) heating and current drive in fusion plasmas. His experience spans experimental research on tokamaks (Alcator C-Mod, DIII-D, EAST, WEST) and dipole confinement devices (Junior), as well as modeling work for future fusion reactors (SPARC, FNSF, CFETR, Tahi) with the goal of achieving and sustaining high performance, fusion-relevant plasma conditions. His recent work on creating machine learning surrogate models for heating and current drive actuators continues to expand to new devices, enabling fast and accurate time-dependent modeling and discharge planning. Dr. Wallace has forged long-lasting professional relationships with colleagues at PPPL, ORNL, GA, LBNL, SFSU, CEA/IRFM, ASIPP, and elsewhere through DOE-funded collaborations, and has more recently made inroads to private sector research as PI on research projects funded by ENI and OpenStar.

Education
  • PhD, Nuclear Science and Engineering, Massachusetts Institute of Technology, 2009
  • BS, Electrical Engineering, Rensselaer Polytechnic Institute, 2003

Magnetic confinement fusion; radio frequency (RF) heating and current drive; ion cyclotron heating; lower hybrid current drive; microwave devices; radiation-tolerant materials

  • 1.Wallace, G., Bai, Z., Sadre, R., Perciano, T., Bertelli, N., Shiraiwa, S., Bethel, E., Wright, J. “Towards fast and accurate predictions of radio frequency power deposition and current profile via data-driven modelling: Applications to lower hybrid current drive”. Journal of Plasma Physics, 88(4), 895880401. (2022). doi:10.1017/S0022377822000708
  • 2.Jung, Minuk, Amy Watterson, and Gregory M. Wallace. "Feasibility Study on Heat Pipes for Radio Frequency Antennas." Fusion Science and Technology (2025): 1-16.
  • 3.G. M. Wallace, Z. Bai, N. Bertelli, E. W. Bethel, T. Perciano, S. Shiraiwa, J. C. Wright; Towards fast, accurate predictions of RF simulations via data-driven modeling: Forward and lateral models. AIP Conf. Proc. 18 August 2023; 2984 (1): 090008. https://doi.org/10.1063/5.0162422
  • 4.G.M. Wallace, et al. “Absorption of lower hybrid waves in the scrape off layer of a diverted tokamak.” Phys. Plasmas 17, 082508 (2010).
  • 5.G. M. Wallace, E. B. Artalejo, M. P. Short and K. B. Woller, "Ultra-Rapid, Physics-Based Development Pathway for Reactor-Relevant RF Antenna Materials," in IEEE Transactions on Plasma Science, vol. 50, no. 11, pp. 4506-4509, Nov. 2022, doi: 10.1109/TPS.2022.3171497.
  • 6.Bonoli, Paul; Wallace, Greg; Shiraiwa, Syunichi; et al. “High Field Side Wave Launch for Steady State Plasma Sustainment.” Nuclear Fusion Vol. 58, No. 12 (2018).
  • 7.G. M. Wallace, T. Bohm & C. E. Kessel Multiphysics Simulations of a Steady-State Lower Hybrid Current Drive Antenna for the FNSF, Fusion Science and Technology, 77:2, 159-171, (2021) DOI: 10.1080/15361055.2020.1858672
  • 8.G.M. Wallace, S. Shiraiwa, et al. “A scoping study for high field side launch of lower hybrid waves on ADX.” IEEE Transactions on Plasma Science, vol.PP, no.99, pp.1-6 (2016).
  • 9.G.M. Wallace, J. Hillairet, P. Koert, Y. Lin, S. Shiraiwa, S.J. Wukitch. “Analysis of double stub tuner control stability in a phased array antenna with strong cross-coupling.” Fusion Engineering and Design, 89, 2748–2754 (2014).
  • 10.G. M. Wallace, et al. “Advances in lower hybrid current drive technology on Alcator C-Mod.” Nucl. Fusion 53 073012 (2013).
  • Selected presentations:
  • 1.Invited oral presentation at the 27th International Atomic Energy Agency Fusion Energy Conference (IAEA FEC). “Novel Radio Frequency Current Drive Systems for Fusion Plasma Sustainment on DIII-D.” October 25, 2018, Ahmedabad, India.
  • 2.Invited oral presentation at the 26th International Atomic Energy Agency Fusion Energy Conference (IAEA FEC). “Influence of the Scrape Off Layer on RF Actuator Performance.” October 21, 2016, Kyoto, Japan.
  • 3.Invited oral presentation at the 21st Topical Conference on Radiofrequency Power in Plasmas (RFPPC2015). “High Field Side Launch of RF Waves: A New Approach to Reactor Actuators.” April 29, 2015, Lake Arrowhead, California.
  • 4.Post-deadline invited oral presentation at the annual American Physical Society (APS) Division of Plasma Physics meeting. “Lower hybrid current drive in the high density multi-pass regime.” November 18, 2011, Salt Lake City, Utah.
  • 5.Invited oral presentation at the IAEA Steady State Operations meeting. “Lower Hybrid Current Drive Studies on Alcator C-Mod.” December 7th, 2010, Vienna, Austria.