Investigations of Poloidal Rotation in the DIII-D Tokamak

Colin Chrystal, General Atomics

April 13, 2016, 11:00am, EBUII 479

Abstract:  Poloidal rotation is an important aspect of tokamak dynamics because of its relation to ExB shear and the associated suppression of turbulent transport. A new poloidal rotation diagnostic was developed on the DIII-D tokamak to test theories that describe poloidal rotation. This new diagnostic uses charge exchange recombination spectroscopy to measure poloidal rotation of impurities in the plasma, and avoids a major source of measurement uncertainty by employing a unique viewing geometry. Measurements made with this diagnostic have shown poloidal rotation increasing during the formation of an internal transport barrier as well as significant disagreements with multiple theoretical predictions in a variety of plasma conditions.   

Bio:  Dr. Chrystal graduated from Caltech in 2007 with a BS in Applied Physics and from UCSD with a PhD in Plasma Physics in 2014. He has been an active researcher at the DIII-D tokamak at General Atomics since 2008, first as a graduate student and now as a postdoc. His research is focused on the transport of momentum in the tokamak plasma, and he has also worked extensively on improving and operating the charge exchange recombination diagnostic.