Since joining the Plasma Fusion Center in 1978, Dr. Greenwald has conducted physics research on the Alcator A, C, and C-Mod tokamaks, including studies of energy and particle transport, pellet fueling, density limits, neutral particle measurements, and studies of energetic ion dynamics. He was part of the design team for Alcator C-Mod. His recent work has focused on the role of critical gradients in determining plasma temperature profiles, on the EDA H-mode regime, and on the role of turbulent transport in determining the tokamak density limit. This latter work is aimed toward defining a "first principals" theory for the limit with the long term goal of obtaining reliable predictions and extrapolations to future machines.

Dr. Greenwald's work in pellet fueling on Alcator C included the discovery of a new regime of enhanced energy and particle confinement. This was the first attainment of an internal transport barrier in a tokamak which is recognized as one of two generic approaches (along with H-Mode) to improving tokamak confinement. Because of the correlation with peaked density profile, the work spurred interest in the hi or Ion Thermal Gradient driven (ITG) mode, now believed to be the principal mechanism for anomalous transport in tokamaks

Dr. Greenwald is head of the Office of Computer Services for MIT's Plasma Science & Fusion Center (PSFC), heads the group responsible for data acquisition and computing for the Alcator C-Mod project and leads the transport program for that experiment . He is a member of the Federal Advisory Committee for Fusion Energy Sciences (FESAC) and represents the U.S. fusion community on the Energy Sciences Network Steering Committee. Dr. Greenwald is a member of the NSTX Program Advisory Committee and a past chairman of the Transport Task Force. He is an APS Fellow and APS/DPP Distinguished Lecturer in Plasma Physics.