Random magnetic fluctuations are ubiquitous in laboratory, space, and astrophysical plasmas. The nonlinear, dynamical evolution of Alfvenic turbulence involving disparate spatial-temporal scales plays an important role in plasma heating, particle acceleration, and transport of mass, momentum, and energy in the interplanetary and interstellar medium. Understanding the basic plasma physics principles of Alfvenic turbulence has recently been identified by the National Research Council (NRC) as one of the key challenges in the next decade of research in solar and space physics. In this project, large scale kinetic simulations of Alfvenic turbulence enabled by recent advances in physics models, numerical algorithms, and the dramatically increased speed and capacity of parallel computers, will be utilized to study the physical processes underlying the spectral cascade from large to small scales and the associated energy dissipation leading to plasma heating. This study will also address many important subjects in basic plasma physics, e.g., the effects of wave-particle resonances, finite Larmor radius effects, and compressibility on the cascade and dissipation of Alfvenic turbulence. The wave-particle nonlinearity and wave-wave nonlinearity will be treated on an equal footing and be delineated. The possibility of stochastic ion heating by sub-cyclotron frequency Alfven waves will also be investigated.
The proposed project will leverage cross-cutting research interests between space plasma physics, magnetic fusion science, and computational sciences. Advanced computational tools developed in magnetic fusion research, such as massively parallel gyrokinetic particle-in-cell simulations, will be introduced to space plasma research. Close collaboration will be undertaken with researchers in the Department of Energy's Scientific Discovery through Advanced Computing (SciDAC) Initiative. The proposed budget will support a postdoctoral researcher and a graduate student working on a Ph.D. thesis, and will help establish an advanced plasma simulation program at the University of California, Irvine. The Principal Investigator of this proposal will provide a training and education program that will incorporate state-of-the-art scientific computing in the physics curriculum. The students will learn massively parallel computation for solving real-world problems. Hands-on training will be provided through participation in the proposed plasma turbulence simulation. The course will be open to students from all science and engineering departments where parallel computing becomes an indispensable research tool. A parallel computing lab will be constructed using the PI's existing startup fund to develop innovative algorithms for parallel computing, data analysis, and advanced visualization in both instruction and research. Both the education and research aspects of the project will be integrated into an Interdisciplinary Center for Computational Science recently proposed at the University of California, Irvine.
