## Research Abstracts Online

January 2010 - March 2011

Main TOC ...... Next Abstract

### University of Minnesota Twin Cities

College of Science and Engineering

School of Physics and Astronomy

# PI: Robert L. Lysak, Associate Fellow

### Numerical Investigations of Solar Wind-Magnetosphere-Ionosphere Coupling

This project is centered on several problems involving the coupling of mass, momentum, and energy between the solar wind, magnetosphere, and ionosphere. This work involves both the development of new codes and the modification and use of existing codes to address the problem of solar wind-magnetosphere-ionosphere coupling. The emphasis during this period continued to be on magnetosphere-ionosphere coupling during magnetospheric substorms, with three specific projects.

The first project applies the group’s three-dimensional model of the propagation of compressional and shear Alfvén waves through the auroral ionosphere and atmosphere. They have implemented a model that incorporates the tilt of the magnetic field with respect to the vertical direction, and we will apply and extend this model to both higher and lower latitudes. A new focus in this research is the development of a nonlinear model for the evolution of currents and fields based on the so-called reduced MHD equations.

The second project continues the investigation of the nonlinear dynamics of the magnetospheric tail using the three-dimensional version of the Total Variance Diminishing (TVD) magnetohydrodynamic (MHD) code provided by the group of Thomas Jones (Astronomy). This code is being used to describe the generation of MHD waves by fast flows in the magnetotail during substorms. The long-term goal of this effort is to combine this code with that described in the first project to make a comprehensive wave code for the magnetosphere.

The third project develops a model of wave propagation that uses kinetic theory to construct an approximate fluid model that can be applied to large-scale waves in the magnetosphere. This will extend the group’s MHD codes to include kinetic effects and allow for the consideration of whistler and lower hybrid waves in the model.

### Group Members

James Crumley, Department of Physics, St. John’s University, Collegeville, Minnesota

Yan Song, Research Associate

Jesse Woodroffe, Graduate Student

Yan Yin, Graduate Student