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| Optical Remote Sensing of the Aurora Borealis |
| Joshua Semeter |
| Thursday, Jun 8, 2006 at 8:00 PM |
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The aurora-borealis is a visible manifestation of an interaction between the hot collisionless plasma of the magnetosphere and the cold collision-dominated plasma of the ionosphere. The transition between these regimes occurs over a relatively narrow range of altitudes from ~80 to 200 km—a region readily probed by ground-based radio and optical sensors. It is also this altitude range where most of the energy in the auroral particle flux is deposited as heat, ionization, and, of course, light. The aurora has considerable diagnostic value in providing the only simultaneous two-dimensional projection of plasma dynamics occurring in the distant magnetosphere. Complementary to the spatial dimension is the spectral dimension, which provides information about the distribution of energy in the causative particle flux, and the composition of the gases with which this flux interacts. Recent applications of multi-spectral imaging in auroral research are combining these dimensions, providing a new perspective on the poorly understood physics of magnetosphere-ionosphere coupling.
This talk will provide a visually stimulating overview of the state of auroral research, with a focus on spectral imaging and multi-sensor analysis techniques. The major outstanding questions in auroral physics will be described in an intuitive fashion, along with a discussion of how emerging sensor technologies---such as electron multiplying CCD’s, and phased-array incoherent scatter radar---will contribute to these questions.
About our speaker
Joshua Semeter received his B.S. degree from the University of Massachusetts at Amherst in 1987, and his M.S. and Ph.D. degrees from Boston University in 1992 and 1997, respectively, all in Electrical Engineering. From 1997 to 1999 he served as a post-doctoral fellow at the Max Planck Institute for Extraterrestrial Physics in Garching, Germany, where he studied auroral plasma dynamics using coordinated rocket and ground-based measurements. From 1999 to 2004 he was a Senior Research Engineer at SRI International in Menlo Park, CA, where his research focused on remote sensing of the high-latitude ionosphere using radio and optical sensors located, primarily, at the NSF research facility at Sondrestrom, Greenland. In September 2004 he joined the faculty of Boston University as an Assistant Professor of Electrical and Computer Engineering.
Dr. Semeter is the recipient of the 2000 NSF Coupling, Energetics, and Dynamics of Atmospheric Regions (CEDAR) Prize Lecture, and the 2004 SRI Presidential Achievement Award for contributions to geospace science. He is an Associate Editor for the Journal of Geophysical Research. He is a member of the American Geophysical Union, and the IEEE Geoscience and Remote Sensing and Signal Processing Societies.
Please join us for a pre-meeting dinner discussion at Changsho, 1712 Mass Ave, Cambridge, MA at 6:00pm before the meeting. |
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