This award is made in response to a collaborative proposal submitted to and reviewed under the NSF/DoE Partnership in Basic Plasma Science and Engineering joint solicitation NSF 08-589. This award funds the research component of the project being conducted by Dr. Andrew Ware at the University of Montana. The research components of Dr. Ware's collaborators, Dr. Eugenio Schuster of Lehigh University and Dr. Mark Gilmore of the University of New Mexico, are funded by the DoE under contract number DE-FG02-09ER55022 and DE-FG02-09ER55062
This research aims to investigate active control of unstable fluctuations, including fully developed turbulence and the associated cross-field particle transport, via manipulation of flow profiles in a magnetized laboratory plasma device. Fluctuations and particle transport will be monitored by an array of electrostatic probes, and flow profiles controlled via a set of biased concentric ring electrodes that terminate the plasma column. The goals of the proposed research are threefold. 1. to develop a predictive code to simulate plasma transport in the linear HELCAT (HELicon-CAThode) plasma device at the University of New Mexico (UNM), where the experimental component of the proposed research will be carried out. 2. to establish the feasibility of using advanced model-based control algorithms to control cross-field turbulence-driven particle transport through appropriate manipulation of radial plasma flow profiles. 3. to investigate the fundamental nonlinear dynamics of turbulence and transport physics. The outcome of the proposed research, although focused on basic plasma physics, will have a strong impact on the scientific advancements that are needed to make nuclear fusion a viable source of energy, and will therefore produce a profound impact on an area of immense importance to the welfare of society. The proposed research will advance discovery while promoting teaching and learning. Due to its multidisciplinary nature, the proposed research plan brings together concepts from plasma physics, computational methods, and controls, with emphasis on experimental validation of the proposed modeling and control solutions. Graduate and undergraduate students will benefit from this unique multidisciplinary experience that will enhance their ability to conduct advanced research, think creatively, take advantage of unique facilities making good use of collaborative arrangements, and work in an individual capacity and as members of a team. The infrastructure for research and learning will be enhanced in each one of the collaborating institution. This collaboration will grant access to graduate and undergraduate students to the HELCAT experimental facility, where they can conduct experiments to validate the modeling and control solutions that result from their research, and will expose each one of the participating students to new research areas.
The focus of this project was the development and testing of a computational model using experimental data from a linear plasma device. This was a collaborative project with researchers at the University of Montana, the University of New Mexico and Lehigh University. The goal of this project was threefold. The first goal was to develop a predictive computational code to simulate plasma transport in the linear HELCAT (HELicon-CAThode) plasma device at the University of New Mexico (UNM), where the experimental component of the proposed research was carried out. The second goal was to establish the feasibility of using advanced model-based control algorithms to control turbulence-driven particle transport through appropriate manipulation of radial plasma flow profiles. Finally, the third and equally important goal was to investigate the fundamental turbulence and transport physics which are integral in a program of affecting their control. This included the development of a cold-ion model to better match the experimental data. We tested different momentum source (biased rings) configurations. Numerical experiments using different biasing configurations for the rings indicated that despite the localized nature of the biased rings, due to the finite radial source width and radial diffusion of azimuthal momentum almost no localized features are observed in the flow profiles. Thus, the impact of the rings is a collective, more global change on the azimuthal flow. The last stage of this project led to the development of an optimizer that selected input parameters to the transport model that lead to the best fits to HELCAT experimental profiles. This work is in collaboration with Prof. Mark Gilmore at the University of New Mexico and Prof. Eugenio Schuster at Lehigh University.
