Executive Summary

September2001

Vision:

A key goal of the DoE Office of Fusion Energy Sciences program is a burning plasma experiment. Energy loss due to anomalous transport is a key issue in determining the size and cost of an experimental facility aimed at studying the physics of burning plasmas. A quantitative understanding of plasma turbulence is a prerequisite to the development of first-principles models of anomalous transport in magnetically confined plasmas. Hence, advancing the understanding of plasma turbulence is central to the OFES program.

Plasma turbulence has been studied through analytic theory and experiment for more than 30 years. The development over the past decade of more powerful computers and of efficient simulation algorithms presents us with another means of studying plasma microturbulence and comparing theory with experiment — direct numerical simulation. Direct numerical simulation complements analytic theory by extending its reach beyond simplified limits, and by accurately modeling the nonlinear development of linear instabilities. Simulation complements experiment because non-perturbative diagnostics to measure quantities of immediate theoretical interest are easily implemented in such simulations, while similar measurements in the laboratory are difficult or prohibitively expensive. Most importantly, direct numerical simulation has achieved a level of fidelity to the underlying plasma physics such that the simulations can be used as a proxy for experiment in testing detailed quantitative predictions regarding plasma turbulence, and as an extension of the theory when interpreting experimental measurements. With a concerted effort, the Plasma Microturbulence Project will enable a complete unification of turbulence theory with the experimental plasma confinement data base.

Major Goals and Technical Challenges:

The Plasma Microturbulence Project will integrate direct numerical simulation of plasma microturbulence into the national magnetic confinement fusion program. We will provide the experimental and theoretical plasma physics communities with a common interface to a suite of complementary, minimally redundant kernels for microturbulence simulation and microstability analysis. Fulfilling this mission will revolutionize the fusion community's ability to interpret experimental confinement data and to test theoretical ideas about turbulence. Our work plan, designed to accomplish this mission, includes:

• Completion of advanced gyrokinetic kernels;

• Development and deployment of a common user interface, including diagnostics and analysis tools; and

• Establishment of a Summer Frontier Center for Plasma Microturbulence (SFC).

The advanced gyrokinetic kernels are the foundation of the microturbulence effort. The SFC is designed to enhance collaboration and coordination among code developers, to solicit input and feedback from the larger plasma microturbulence community, to facilitate interactions with the wider scientific community, and to train an expanding user community to use the tools we develop. Finally, a common user interface, with sophisticated diagnostics and analysis tools, will expand the impact of microturbulence simulation well beyond the existing small group of code developers.

Major Milestones and Activities:

Connections to Other Centers:

The National Collaboratory to Advance the Science of High-Temperature Plasma Physics for Magnetic Fusion for network access to the national magnetic fusion experimental data base, network authentication, and MDS+ tools.