This award is made in response to a proposal submitted to and reviewed under the NSF/DOE Partnership in Basic Plasma Science and Engineering joint solicitation NSF 09-596. The award provides funds to support undergraduate participation in the overall research effort, which is being funded separately by the DOE under contract to UCLA (Grant DE-FG02-10ER55082).
This project consists of basic studies of non-diffusive transport in magnetized plasmas. By non-diffusive it is meant that the transport of fundamental macroscopic parameters of a system, such as temperature and density, does not follow the standard diffusive behavior predicted by a classical Fokker-Planck equation. Contemporary studies in broad areas of science are increasingly identifying the important role of non-diffusive transport. Numerous examples can be found in widely different fields such as biology, geology, atmospheric sciences, and plasma science. The project team consists of Prof. George Morales (PI) and Dr. James Maggs (co-PI) at UCLA, a senior collaborator, Dr. Diego del-Castillo-Negrete at Oak Ridge National Laboratory, and a graduate student at UCLA, Adam Kullberg. The project aims to expand and develop mathematical descriptions, and corresponding numerical modeling, of non-diffusive transport to incorporate recent perspectives derived from basic laboratory experiments performed in the LAPD-U device at UCLA. The project will proceed by first tackling simpler issues and sequentially increasing the complexity to a level where experimental comparisons are possible and new experiments can be designed. The intellectual merit of this project is that it provides a unique connection between modern advances in the mathematical description of non-diffusive transport and basic plasma experiments in which the role of fluctuations can be related, under controlled conditions, to the transition between classical and anomalous transport.
The broader impacts include the generation of basic insight useful to magnetic fusion and space science researchers, completion of a Ph.D. dissertation in broad areas of national interest, establishing a valuable exchange between academic and national laboratory researchers, and promotion of interest in science through community outreach events and classroom instruction.
The NSF support of undergraduate participation adds a broader educational impact through the early-year training of students by introducing them to scientific research as a possible career path.
Project Objective: The project aims to expand and develop mathematical descriptions, and corresponding numerical modeling, of non-diffusive transport to incorporate new perspectives derived from basic transport experiments performed in the LAPD device at UCLA, and at fusion devices throughout the world. By non-diffusive it is meant that the transport of fundamental macroscopic parameters of a system, such as temperature and density, does not follow the standard diffusive behavior predicted by a classical Fokker-Planck equation. The appearance of non-diffusive behavior is often related to underlying microscopic processes that cause the value of a system parameter, at one spatial position, to be linked to distant events, i.e., non-locality. In the LAPD experiments the underlying process can be traced to large amplitude, coherent drift-waves that give rise to chaotic trajectories. Overview: Since the last reporting period, major results have been obtained in several components of the project. The new findings impact general areas of research including statistical physics, chaos theory and magnetic fusion experiments. The major research highlights are: 1) The long-standing question related to the origin of the observed broadband spectrum of deterministic chaos has been resolved; 2) A practical formulation and associated numerical methodology has been developed to describe fractional transport in two dimensions, including the effect of boundaries; 3) It has been shown that published results of measured fluctuations in major fusion devices throughout the world indicate that the underlying physics of edge transport is deterministic chaos. The various efforts have led to three published manuscripts (in Physical Review E—Rapid Communications, Plasma Physics and Controlled Fusion, and Physical Review E—Statistical Physics), two conference presentations (at the APS Plasma Physics Division annual meeting, and EPS/ICPP joint meeting) and two invited papers (at EPS/ICPP joint meeting, and EFTSOMP 2012). The results related to "chaotic dynamics and electron temperature transport" have been highlighted in a LabTalk summary by the IOP Science editors. The graduate student working in the project, Adam Kullberg, is making great progress in his Ph.D. dissertation. It is expected that he will graduate at the end of 2013. An undergraduate student, Sam Taimourzadeh, doing apprenticeship research in the project will be attending graduate school at UC Irvine in the Fall Quarter of 2013. Intellectual merit: Advanced fractional transport formulation to new levels of experimental relevance, explained origin of exponential spectrum of chaos, identified presence of chaotic dynamics at the edge of a broad class of plasma devices. Broader impacts: One Ph.D. student thesis, one undergraduate student trained and admitted to graduate school, established broader contacts with nonlinear dynamics and turbulence communities, delivered lectures to Latin American scientists.