3-D Density Measurements for the ITER Disruption Mitigation Test Stand and NCSX

Magnetic Fusion Energy holds out the hope of supplying clean energy to the world and eliminating the causes of global warming. While research to date has shown high probability that an ignited magnetic fusion device can be built (e.g., the ITER Project), present research is focused on making fusion reactors more attractive and usable devices. Improving confinement and fueling in magnetic fusion devices can significantly improve the attractiveness of reactors by making them smaller, and easier to ignite and maintain. To this end, a digital holographic imaging device ¿ which provides three dimensional (3D) density, particle transport, and fueling data, at high speed and high spatial resolution ¿ would make it possible to study and understand both transport and fueling with greatly increased resolution. Therefore, this project will develop a digital holographic camera system (320x256 pixels or 160x128 pixels, programmable) that uses a pulsed CO2 laser light source. The camera will provide views with 82,000 or 20,000 separate chordal measurements of the plasma under study, at frame rates of 420 or 1,300 frames per second (or even higher frame rates at lower spatial resolutions). This approach will provide differential, implicitly 3D particle transport measurements by providing the time evolution of fine-grained plasma density profiles at spatial resolutions never previously obtained. Phase I will fabricate a low-cost infrared (CO2 laser) demo system with a low-cost (low speed) digital infrared camera. The camera will demonstrate feasibility at infrared (CO2) wavelengths. During Phase II, a full CO2 laser digital holography system will be developed for installation on the NCSX stellarator fusion physics research device. Commercial Applications and other Benefits as described by the awardee: An infrared digital holography system for fusion energy plasma diagnostics should lead to improved magnetic fusion energy generation. Additionally, the development is expected to result in the commercialization of unique measurement systems in a number of electronics and manufacturing industries. For example, the $3B semiconductor diagnostic equipment market needs a capability for high-volume, cost-sensitive micron-scale measurements, which potentially could be addressed by digital holography operating in the infrared. Also, applications for infrared digital holography exist in the $50B flat panel display and $5B micro-electro-mechanical structures (MEMS) industries.