**Special Physics Colloquium** Imaging the Physics of Magnetically Confined Fusion

Event Dates: 

Thursday, February 11, 2016 - 2:00pm

CTQM Seminar Type: 

  • Related Seminar Series

Speaker Name(s): 

Benjamin Tobias

Speaker Affiliation(s): 

Princeton Plasma Physics Laboratory

Abstract, Event Details: 

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.