HR: 1340h
AN: SM23A-0464    [Abstracts]
TI: Observations of Narrow-Band $\sim$60-100 Hz Waves at High Auroral Latitudes
AU: * Kim, H
EM: hyomin.kim@unh.edu
AF: University of New Hampshire, Morse Hall 39 College Road, Durham, NH 03824 United States
AU: Lessard, M R
EM: marc.lessard@unh.edu
AF: University of New Hampshire, Morse Hall 39 College Road, Durham, NH 03824 United States
AU: LaBelle, J
EM: james.labelle@dartmouth.edu
AF: Dartmouth College, HB 6127 Wilder Laboratory, Hanover, NH 03755 United States
AU: Johnson, J R
EM: jrj@pppl.gov
AF: Princeton University, Plasma Physics Laboratory, Princeton, NJ 08543 United States
AU: Weatherwax, A T
EM: aweatherwax@siena.edu
AF: Siena College, Physics Department, Loudonville, NY 12211 United States
AB: ELF magnetic pulsations have been measured using a new induction coil magnetometer having a frequency response in the ELF (Extremely Low Frequency) range ($\sim$0.1-250 Hz), which has recently been installed at South Pole Station. An initial survey of the first month of data revealed very interesting phenomena, including narrow-banded ELF pulsations with slowly varying frequencies and ELF 'hiss' in the $\sim$10-130 Hz frequency range. The narrow-band signatures maintain their bandwidth as their frequencies change slowly, typically from 100 to 60 Hz over the course of the order of $\sim$40-90 seconds. Although the narrow-band waves have a signature somewhat similar to VLF (Very Low Frequency) whistlers in the sense that their frequencies typically decrease with time, their duration and frequency range are much different than whistlers; they also show an unusual characteristic where their frequency often increases before it decreases. An initial survey of these events shows a peak in their occurrence distribution near the pre-midnight region, implying a possible association with substorm occurrences, a result that contrasts sharply with the only two other published studies of these waves. In this presentation, we show results of a more complete study, including polarization characteristics of these waves, comparison with other data to determine the geophysical conditions present when they occur and a more complete statistical result of their occurrence distribution.
DE: 2704 Auroral phenomena (2407)
DE: 2784 Solar wind/magnetosphere interactions
DE: 2788 Storms and substorms
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting