Woodruff School of Mechanical Engineering

NRE 8011/8012 and MP 6011/6012 Seminar

Nuclear & Radiological Engineering and Medical Physics Programs


Survey of Current DIII-D Research


Dr. Richard Groebner


Scientist at General Atomics in San Diego


Thursday, November 15, 2018 at 11:00:00 AM


Boggs Building, Room 3-47


Weston Stacey


Survey of Current DIII-D Research Richard J. Groebner General Atomics, San Diego, CA A brief survey of recent results from the DIII-D tokamak, with an emphasis on H-mode pedestal studies, will be presented. DIII-D, operating since 1986, is the largest magnetic plasma confinement machine operating in the US. DIII-D has a strong research focus on developing the physics basis to understand and predict performance in the International Thermonuclear Experimental Reactor (ITER), currently being constructed in France, as well as in future fusion reactors. Examples of research to address important concerns posed by the ITER project are studies to eliminate and mitigate disruptions and studies to validate theoretical models to predict temperature and density profiles in tokamaks. Looking towards ITER and future machine, DIII-D works to improve the tokamak concept, with an example being research to study the Super H-mode regime of improved tokamak performance, predicted by a theoretical model. Motivated by needs to develop integrated operational scenarios for future machines, DIII-D research has put a significant focus on “core-edge integration”, the coupling of high performance core plasmas to the low temperature, high density boundary plasmas required in future machines. The H-mode pedestal is the interface between the hot core and cool boundary and recent studies have explored the physics of the pedestal density at this interface. Research has focused on improving understanding of the neutral fuelling as well as transport processes that combine to form the density pedestal. Work supported by US DOE under DE-FC02-04ER54698.


Richard J. Groebner is a Scientist at General Atomics in San Diego, California. He received his PhD in physics from the University of Wisconsin-Madison in 1979. Since then, he has been performing experimental research in magnetic fusion energy at General Atomics on the Doublet III (1979-1985) and the DIII-D tokamaks (1986–present). His primary research interests have focused on the physics of energy and particle transport in high temperature, magnetically confined plasmas and on the physics of the H-mode confinement in tokamaks. His H-mode research has included a strong focus on the physics of the pedestal in energy and particles at the boundary of H-mode discharges. A significant portion of his career has also been spent on the development, operation and analysis of Charge Exchange Recombination Spectroscopy diagnostics, used for measurements of ion temperature, rotation and density in high temperature fusion plasmas. Dr. Groebner is currently leader of the Pedestal and ELM Physics Group in the Experimental Sciences Division of DIII-D. He was awarded the Excellence in Plasma Physics Award in 2001.


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