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Oral Defense Abstracts

Date: Friday, May 23, 1997
Time: 12:00 pm (Refreshments at 11:45 pm)
Location: Durand 450

Special University Ph.D. Oral Examination
Precipitation of Radiation Belt Electrons by Obliquely-Propagating Lightning-Generated Whistler Waves
Dave Lauben
Department of Electrical Engineering

Every lightning discharge radiates brief, intense electromagnetic fields which may penetrate the lower ionosphere and couple to the whistler mode in the magnetosphere. As these circularly polarized waves traverse the magnetosphere they interact with gyrating trapped electrons, causing a percentage to be scattered and precipitated onto the upper atmosphere.

In this new formulation we consider the case of general whistler wave propagation in a smoothly-varying magnetosphere where the ray paths are not necessarily (Earth magnetic) field aligned, and where the wavenormal angle (k-vector) may take on any allowed value for the anisotropic media.

We present quantitative calculations of transient electron fluxes resulting from individual lightning flashes, and highlight a case where a single discharge can cause a precipitation flux of E>100 keV electrons exceeding 10 milli-ergs/cm^2/s for up to 1 second, deposited over a spatial region roughly 6 x 10 degrees centered some 14 degrees poleward of the source.

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