Prof. Mark Koepke, University of West Virginia
Members of the Space Physics group at PPPL, Drs. Jay Johnson and Peter Damiano, are collaborating with Professor Mark Koepke of West Virginia University (and his collaborator Prof. David Knudsen at the University of Calgary) on nonlinear time-stationary inertial Alfven waves that can develop where convective magnetospheric plasma flow intersects with regions of magnetic-field-aligned electric current. Such waves are nonstationary, meaning its electric field pattern does not oscillate in time, but instead oscillates in space, permitting steady-state electric field regions that can accelerate electrons parallel to the background magnetic field. Steady-state electron acceleration can lead to discrete auroral arcs, in other words, bands of light in the upper atmosphere caused by electron-impact excitation of high-altitude gases like oxygen and nitrogen that give off light as they de-excite. Since steady convective flows are ubiquitous in the tail region of the Earth's magnetosphere and in the auroral regions of the Earth's ionosphere, these stationary waves have garnered much interest in possibly explaining the formation of long-lived auroral arcs (see picture below), but have yet to be studied in computer simulations. Peter Damiano and Jay Johnson, are working with Professor Koepke to model these waves under the predicted natural space conditions using a hybrid particle-fluid simluation model and to compare results with theoretical and laboratory studies of stationary waves being conducted by his group at West Virginia.
Photograph of a long-lived auroral arc entitled, "A Starry Night in Iceland", courtesy of NASA.