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Observations of a Unique Type of ULF Wave by Low-Altitude Space Technology 5 SatellitesWe report a unique type of ULF waves observed by low-altitude Space Technology 5 (ST-5) constellation mission. ST-5 is a three-microsatellite constellation deployed into a 300 x 4500 km dawn-dusk and Sun-synchronous polar orbit with 105.6deg inclination angle. Because of the Earth's rotation and the dipole tilt effect, the spacecraft's dawn-dusk orbit track can reach as low as subauroral latitudes during the course of a day. Whenever the spacecraft traverse the dayside closed field line region at subauroral latitudes, they frequently observe strong transverse oscillations at 30-200 mHz, or in the Pc2-3 frequency range. These Pc2-3 waves appear as wave packets with durations in the order of 5-10 min. As the maximum separations of the ST-5 spacecraft are in the order of 10 min, the three ST-5 satellites often observe very similar wave packets, implying these wave oscillations occur in a localized region. The coordinated ground-based magnetic observations at the spacecraft footprints, however, do not see waves in the Pc2-3 band; instead, the waves appear to be the common Pc4-5 waves associated with field line resonances. We suggest that these unique Pc2-3 waves seen by ST-5 are in fact the Doppler-shifted Pc4-5 waves as a result of rapid traverse of the spacecraft across the resonant field lines azimuthally at low altitudes. The observations with the unique spacecraft dawn-dusk orbits at proper altitudes and magnetic latitudes reveal the azimuthal characteristics of field line resonances.
Document ID
20120012013
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Le, G.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Chi, P. J.
(California Univ. Los Angeles, CA, United States)
Strangeway, R. J.
(California Univ. Los Angeles, CA, United States)
Slavin, J. A.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 26, 2013
Publication Date
August 2, 2011
Publication Information
Publication: Journal of Geophysical Reaearch
Volume: 116
Subject Category
Geophysics
Report/Patent Number
GSFC.JA.01246.2012
Funding Number(s)
CONTRACT_GRANT: NNX08AF3JG
Distribution Limits
Public
Copyright
Other

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