College of Science & Engineering
This group is creating models of the propagation of magnetohydrodynamics (MHD) waves through the magnetosphere. This effort includes three separate but related projects.
- The researchers have developed a global three-dimensional MHD code to describe the interaction of MHD waves with the collisional ionosphere. This model includes the effects of Hall conductivity in the ionosphere as well as the finite magnetic zenith angle (the angle between the magnetic field direction and the vertical). The model also includes the ability to directly calculate ground magnetic signatures of these waves. The reseachers have extended the model to include 3D variations in the ionospheric conductivity and plasma density. They are applying these new features of our model to help understand the seasonal and daily dependence of ULF wave propagation in the magnetosphere and compare the model results with data from ground magnetometers as well as the Van Allen Probes that are studying the inner magnetosphere.
- The researchers have also developed a more localized code that can describe the role of MHD waves in the development of parallel electric fields in the auroral zone. This model includes parallel electric fields due to electron pressure and inertia as well as a phenomenological model of Landau damping. The group is implementing this model in the full dipole coordinates used in the project above. They also plan to begin an effort to model electron kinetics in the auroral zone in order to understand the development of plasma double layers on auroral field lines.
The researchers have begun a program to investigate Alfven waves in Jupiter's magnetosphere using codes based on their earlier codes. Adapting these codes to Jupiter has involved changing the scale factors in the fundamental equations and developing a new model for the stretched field lines at Jupiter caused by the rapid rotation of the planet. The group also will implement a plan to drive the system by ionospheric motions, an aspect not present at Earth but likely dominant at Jupiter due to its rotation and the turbulent nature of its ionosphere and atmosphere. This aspect is motivated by recent observations by the Juno satellite in polar orbit around Jupiter that is measuring auroral particles and fields close to the planet for the first time.