The Woodruff School

SUMMARY

In the international effort to successfully build and operate the ITER tokamak, greatly improving the understanding of Edge Localized Mode (ELM) instabilities is one of the most important major research topics. These ELM instabilities are characteristic of tokamak operations in
high-confinement mode (H-mode), cyclically ejecting large ion fluxes onto the inner surfaces of the tokamak machine that are harmful to both performance and the machine itself.

ELMs occur near the surface of the tokamak�s plasma torus, and are largely driven by transport processes in this �edge� region. The plasma edge is a region where powerful electric fields and other forces are dominant, and plasma transport is poorly understood. The major goal of this research is
to use measured data, applied knowledge, modeling codes, and a specific theoretical framework to analyze plasma transport in the edge during "ELMing H-mode" tokamak operation. I hope to contribute to a better dynamic understanding of how plasma transport, precursors to ELM destabilization, and plasma parameters are related, and gain some insight into how we may be able to control ELMs - two significant contributions to the field. With these insights, it may be possible to learn to directly influence integral parts of edge transport, allowing active maximization of plasma
performance and active mitigation or disruption of the damaging outflows associated with ELMs.

The specific methods this research will use include: data gathering and analysis from the DIII-D database, operation and use of the data preparation scripts and programs to process the data into a useable form, incorporating the data into the GTEDGE plasma modeling code to calculate its effect on the properties of the entire plasma, extracting and presenting the results, and analyzing and interpreting the results using experience, knowledge, and a theoretical framework for edge plasma transport. This process will be applied to multiple DIII-D discharges and ELM types to maximize the generality of the analysis results.

SUBJECT:	Ph.D. Proposal Presentation

BY:	John-Patrick Floyd

TIME:	Wednesday, November 6, 2013, 3:30 p.m.

PLACE:	Boggs, 3-47

TITLE:	Plasma Transport Evolution in the Edge Pedestal Region during DIII-D H-mode Operation

COMMITTEE:	Dr. W. M. Stacey, Chair (NRE) Dr. A. Erickson (NRE) Dr. T. Utschig (NRE/CETL) Dr. R. T. McGrath (GTRI/GT/MSE) Dr. R. J. Groebner (General Atomics)

SUMMARY In the international effort to successfully build and operate the ITER tokamak, greatly improving the understanding of Edge Localized Mode (ELM) instabilities is one of the most important major research topics. These ELM instabilities are characteristic of tokamak operations in high-confinement mode (H-mode), cyclically ejecting large ion fluxes onto the inner surfaces of the tokamak machine that are harmful to both performance and the machine itself. ELMs occur near the surface of the tokamak�s plasma torus, and are largely driven by transport processes in this �edge� region. The plasma edge is a region where powerful electric fields and other forces are dominant, and plasma transport is poorly understood. The major goal of this research is to use measured data, applied knowledge, modeling codes, and a specific theoretical framework to analyze plasma transport in the edge during "ELMing H-mode" tokamak operation. I hope to contribute to a better dynamic understanding of how plasma transport, precursors to ELM destabilization, and plasma parameters are related, and gain some insight into how we may be able to control ELMs - two significant contributions to the field. With these insights, it may be possible to learn to directly influence integral parts of edge transport, allowing active maximization of plasma performance and active mitigation or disruption of the damaging outflows associated with ELMs. The specific methods this research will use include: data gathering and analysis from the DIII-D database, operation and use of the data preparation scripts and programs to process the data into a useable form, incorporating the data into the GTEDGE plasma modeling code to calculate its effect on the properties of the entire plasma, extracting and presenting the results, and analyzing and interpreting the results using experience, knowledge, and a theoretical framework for edge plasma transport. This process will be applied to multiple DIII-D discharges and ELM types to maximize the generality of the analysis results.