HR: 1340h
AN: SM23B-1406    [Abstracts]
TI: Direction of Arrival Measurements of Auroral Medium Frequency Burst Radio Emissions at Toolik Lake, AK
AU: * Bunch, N L
EM: nicholas.bunch@dartmouth.edu
AF: Dartmouth College, 6127 Wilder Lab, Hanover, NH 03755, United States
AU: LaBelle, J W
EM: james.labelle@dartmouth.edu
AF: Dartmouth College, 6127 Wilder Lab, Hanover, NH 03755, United States
AU: Hughes, J M
EM: John.Hughes@erau.edu
AF: Embry-Riddle Aeronautical University, 600 South Clyde Morris Boulevard, Daytona Beach, FL 32114, United States
AU: Weatherwax, A T
EM: aweatherwax@siena.edu
AF: Siena College, Department of Physics, Londonville, NY 12211, United States
AU: Ye, S
EM: sy@space.physics.uiowa.edu
AF: University of Iowa, 203 Van Allen Hall, Iowa City, IA 52242, United States
AU: Lummerzheim, D
EM: lumm@gi.alaska.edu
AF: Geophysical Institute, University of Alaska, 903 Koyukuk Drive, Fairbanks, AK 99775, United States
AB: MF burst is an impulsive radio emission of auroral origin detected by ground-based instruments approximately between 1,300 and 3,700 kHz, and associated with substorm onsets. Its exact generation mechanism is unknown, though it has been speculated that it arises from mode conversion radiation. To discover the generation mechanism and the relation of MF burst to auroral processes, Dartmouth has deployed radio interferometers in Alaska, Northern Canada, Greenland, and Antarctica, including a three-element interferometer deployed at Toolik Lake Field Station in Alaska in 2006. This instrument measured spectra, amplitudes, and directions of arrival (DOA's) of over 47 MF burst events occurring between November 30, 2006 and May 26, 2007. These represent the first DOA measurements ever reported for the impulsive MF burst phenomenon. Preliminary analysis shows that the events originated from a wide range of directions in the sky, with all azimuths represented in the distribution of DOA's. The DOA of each individual event is well-defined, however. Many events show apparent motion, with southward motions more common than northward among the subset of events analyzed so far. Some of the events were detected simultaneously on an interferometer deployed at Kaktovik, Alaska, 400 km away. The all-sky imager at Toolik Lake was also operational for some events. Further analysis of these data promises to reveal first information about the locations and motions of MF burst sources, a first step towards discovering the generation mechanism of this mysterious radio emission and its relation to auroral processes.
DE: 2407 Auroral ionosphere (2704)
DE: 2772 Plasma waves and instabilities (2471)
DE: 6964 Radio wave propagation
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting