University of Minnesota
School of Physics & Astronomy

Physics and Astronomy Colloquium

Wednesday, May 6th 2009
3:35 pm:
Speaker: Professor Eric Donovan, University of Calgary
Subject: Using the Aurora to Remote Sense Plasma Physical Processes in Near-Earth Space
Refreshments served in Room 216 Physics at 3:00 p.m. this week only.

Near-Earth space (or GeoSpace) is a plasma environment which sits between the Earth's atmosphere and the interplanetary medium. This region is populated by plasma that originates from the solar wind as well as our atmosphere, and is host to dynamic physical processes that are interesting not only in their own right, but also as examples of processes at work in the solar corona and more distant cosmic plasma systems. Large and small-scale electrodynamics are responsible for, among other processes, the Northern and Southern Lights, also known as the Aurora Borealis. While GeoSpace is close by, it is notoriously difficult to study. It is virtually impossible to image GeoSpace directly, and even fleets of satellites flown with state-of-the-art instrumentation provide point measurements within a vast region of space. The topology of the GeoSpace environment is largely controlled by the terrestrial magnetic field. The entire region is connected along magnetic field lines to the Earth's upper atmosphere, one consequence of that connection being the aforementioned Aurora Borealis. For more than fifty years, researchers have been struggling to develop the aurora as a means of remote sensing GeoSpace dynamics, providing a crucial compliment to direct satellite observations. In this talk, I will provide a brief overview of GeoSpace and some of the big questions that space physicists are addressing. I will focus on the aurora, and how we are now using state-of-the-art auroral observations to explore some specific questions such as how small-scale dynamics such as reconnection and MHD instabilities affect the global system topology in dramatic events called magnetic substorms.

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