CDS&E: AST: Collaborative Research: Computational science in support of space missions: plasma turbulence modeling on geodesic meshes

University Of Notre Dame, Notre Dame IN

Investigators

Abstract

In situ and remote observations in the solar wind and other astrophysical environments reveal that the plasma invariably possesses anisotropic temperatures. This requires non-ideal magnetohydrodynamics (MHD), but so far there has been no consistent approach to modeling the necessary physics. The most significant open question in heliophysics is to explain the extraordinarily high temperature of the solar corona and hence the origin of the solar wind. Forthcoming observations should provide a wealth of new information, but interpretation is likely to find current theory considerably wanting. This project will go beyond the MHD approximation using the most sophisticated computational algorithms and combining the unique strengths of the research team. The calculational tools developed to analyze solar activity will yield a better understanding of how solar storms arise and thus enhance predictive space weather capabilities. The research team is heavily involved in the teaching and dissemination of computational physics with significant workforce development impact. Recent advances in plasma theory provide closures of the fluid hierarchy incorporating anisotropic pressures, reproducing linear Landau damping to any desired precision, and demonstrating convergence of the fluid and collisionless kinetic descriptions. This work will integrate an advanced description of the coronal and inner heliosphere plasma into models of wave propagation, turbulence transport, and anisotropic heating. It will enable solution of the Chew-Goldberger-Low (CGL) equations, including a Hall term, on adaptive, spherical meshes with physics-based turbulent closures. This involves three highly innovative tasks: 1) a correct treatment of the Hall-CGL equations; 2) development of adaptive mesh refinement for spherical meshes; 3) a weakly compressible model for turbulence which enables a physics-based estimate of the transport coefficients for anisotropic thermal conduction in plasmas with anisotropic pressure distributions. The resulting code will take the astrophysics and space science communities to the next level of sophistication in modeling astrophysical plasmas. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.