Studies of turbulence, transport and flows in the Large Plasma Device

University Of California-Los Angeles, Los Angeles CA

Investigators

Abstract

The goal of this project is to gain understanding of the interaction between flows, turbulence, and transport in a laboratory plasma. Experiments will be performed using the Large Plasma Device (LAPD), which is part of the Basic Plasma Science Facility at UCLA. The work would build on the recent observation of a particle confinement transition triggered by bias-driven rotation in LAPD. In the proposed work, focus will be given to the role of parallel boundary conditions in turbulence, transport and flows in LAPD. A set of limiters will be constructed in order to establish well-defined, yet changeable, parallel boundary conditions in the edge of LAPD. Modifications in turbulence, transport, and driven and spontaneous flows with parallel boundary conditions will be investigated. A second focus will be on angular momentum transport and flow generation in LAPD, emphasizing a study of the role of intermittent convection in these processes. In addition, a set of topics for alternate lines of research are discussed, including studies of the scaling of the transition threshold with plasma parameters, and the axial dependence of driven flows and the confinement transition. The intellectual merit of the proposed research stems from the fundamental importance of turbulence, transport, and flows in a wide range of plasmas. The proposed detailed study of the interplay between transport, turbulence and flows will have an impact on a wide range of subfields of plasma physics, including magnetic confinement fusion, and space and astrophysical plasma physics. The broader impacts of the proposed work would be realized in both the research and educational activites. A major focus of the proposal is the training of one graduate student, working toward a PhD, and one undergraduate student. The proposed work will complement an existing effort in collaboration with LLNL to compare measurements in LAPD to predictions of the 3D Braginskii fluid code BOUT. The detailed measurements possible in LAPD provide a significant test of the predictive capabilities of a simulation code such as BOUT. Establishing a predictive capability in turbulence and transport in magnetized plasmas is important in advancing understanding of fundamental plasma processes in a variety of settings, but is especially critical to progress in magnetic fusion energy research. The work proposed here will, in part, help establish LAPD as an experimental platform for testing the capabilities of current (e.g., BOUT) and planned (e.g., edge kinetic simulation) massively-parallel turbulence simulation codes. This proposal was submitted to the NSF-DoE Partnership in Plasma Science and Engineering joint solicitation 08-589. This award is being funded by the Plasma Physics Program in the Division of Physics.