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Very Low Frequency Research |
Very Low Frequency (VLF, 3-30 kHz) research at the University of Florida focuses on the energetic and electrodynamic coupling of lightning energy to the lower ionosphere and upper mesosphere (~60-120 km altitude).
Lightning energy may both directly and indirectly couple to this region of the atmosphere. Direct coupling may be brought about, for instance, by the ionospheric absorption of the electromagnetic pulse (EMP) emanated during a lightning return stroke. In addition to the effects of EMP, dielectric breakdown of the high altitude atmosphere may occur under the influence of strong quasi-static electric fields, resulting in the fantastic luminous phenomena known as sprites. Lightning energy may also couple to the ionosphere in an indirect manner by first coupling into near-Earth space and affecting the precipitation of electrons from the Earth's radiation belts. These precipitating electrons may deposit in the lower ionosphere while creating a swath of secondary ionization that may in turn be detected using the sensitive VLF remote sensing method.
At the University of Florida, we experimentally investigate the ionospheric disturbances created by these and related physical processes by detecting and analyzing the scattering of VLF fields from the ionospheric disturbances (i.e., the VLF remote sensing method). As part of the Lightning Research Laboratory at the University of Florida, we simultaneously acquire near-field wideband (1 Hz - 20 MHz) data typically within ~1 km of the causative lightning flash in order to fully characterize the types of lightning responsible for the observed VLF events.
In addition to lightning-related VLF events, we also investigate ionospheric disturbances created in a controlled environment. In participation with the Polar Aeronomy and Radioscience (PARS) program and the High Frequency Active Auroral Research Program (HAARP), we conduct controlled experiments using a high power, high gain HF transmitter in Alaska to research the nonlinear absorption of High Frequency electromagnetic energy by the ionosphere.
For inquiries, please contact:
Electrical and Computer Engineering Department
University of Florida
Gainesville, FL 32611
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Electrical and Computer Engineering Department
