Event DetailsEvent Dates: Thursday, February 11, 2016 - 2:00pmSeminar Location: OtherSeminar Location Other: Duane Physics Room F1117 (Commons Room)Speaker Name(s): Benjamin TobiasSpeaker Affiliation(s): Princeton Plasma Physics Laboratory Seminar Type/SubjectScientific Seminar Type: Physics Department ColloquiumEvent Details & Abstract: Electron Cyclotron Emission Imaging (ECEI) and Microwave Imaging Reflectometry (MIR) are powerful visualization tools that are purpose built for tokamak research, and they have become integral to experiments at the cutting edge of fusion science. They provide unique data that was simply not available to previous generations of scientists and bring us closer than ever to understanding and controlling instabilities. 2D and 3D images of the core plasma help to validate modeling of Alfvénic oscillations that can limit plasma self-heating in a burning reactor by diagnosing their interaction with energetic ions. Images of the edge plasma help to explain how and why transients occur, and what techniques can excite benign modes to regulate the stability of this region. To address the most dangerous eventuality, a rapid and violent disruption of plasma confinement, we apply these tools in the study of helical modes that tear the internal magnetic surfaces. The vast majority of tokamak disruptions are attributed to these tearing modes, and using microwave imaging data we are able to validate magnetohydrodynamic (MHD) modeling, quantify the forces omitted by single fluid resistive theory, and accurately prescribe inputs to more sophisticated analysis that can help us understand the successes and failures of disruption avoidance and mitigation techniques.