Project description:
This collaboration, in partnership with the Max Planck Institut für Plasmaphysik and MIT, is a continuation of a project that I initiated in 2014 and for which I secured original funding from the US Department of Energy. Since my arrival at SUNY Cortland I have continued to work on this project and spent the majority of my 2018 summer in Germany. I secured additional funding for a student so that Mr. Nathaniel Rose could work with me on an optics design problem over the summer. This work has continued for approximately two years. I continue to do diagnostic design and development work for this project in support of the next experimental campaign that is currently scheduled to begin in 2022.
My contribution to the Wendelstein 7-X project was the design and construction of a phase contrast imaging (PCI) diagnostic. This is a visualization system that can be liked to an interferometer with an internal-reference that produces images of fluctuations about the mean. In the case of imaging plasmas, we observe fluctuations in the electron density induces by waves and instabilities. Our output is a 1D image composed of 32 pixels. While this is certainly a coarse image by any other standard, it is sufficient to resolve many important properties of the fluctuations we observe, including frequency, wavelength and direction of propagation.
In relation to the big picture of physics research on the Wendelstein 7-X stellarator, a device built to study the physics of plasma confinement in pursuit of fusion energy, my PCI diagnostic is centrally important to identification of conditions under which improved confinement occurs. Turbulence is generally the enemy of efficiency, allowing energy to escape the plasma more readily, thereby resulting in cooler core temperatures and lower fusion reactivity. By monitoring the fluctuations (i.e. turbulence) in the core of the plasma we can develop a better understanding of how the external control parameters affect the fusion region of the plasma.
Publications:
1. Overview of the W7-X PCI diagnostic
2. Suppression of core turbulence in W7-X
3. A heterodyne PCI system for ICE detection
4. The upgraded W7-X PCI diagnostic system
Student Research:
Summer 2018
Student: Nate Rose, internship at the Institute fur Plasmaphysik, Greifswald, Germany
Project: Development of a calculation tool to aid in the optical design process
Final presentation and final report
Fall 2016 & Winter 2017, MIT
Student: Jeannette Maisano-Brown
Project: Development and testing of an arrayed light source for W7-X PCI detector calibration
Related Developments:
Optictool – an intuitive optical design environment built by myself and Nate Rose over the last two years.