Plasma Diagnostics

I am currently a diagnostic scientist working on the DIII-D fusion reactor. As taken from the DIII-D website: “The mission of the DIII-D Research Program is to establish the scientific basis for the optimization of the tokamak approach to fusion energy production. The DIII-D Program is a cornerstone element in the national fusion program strategy.” Work done at DIII-D covers plasma diagnostics, control, and plasma physics. Some of the work is also relevant for the International Thermonuclear Reactor (ITER) in southern France. ITER is the intermediate step between current tokamaks around the world and the first tokamak envisioned to generate power.

I am working on a Thomson Scattering system measuring the electron temperature and density inside the plasma. We use 11 Nd:YAG pulsed lasers (20Hz and 50Hz) operating at nominally 1J per pulse. The light from these lasers scatter off of electrons in the plasma, which gets blue shifted depending on the electron temperature. The electron density is computed based on how many photons we collect. The light is collected at 70 locations within the reactor and the diagnostic provides one of the few self-referenced measurements of plasma parameters.