タイトル | Observations of Field Line Resonances by Low-Altitude ST-5 Satellites |
本文(外部サイト) | http://hdl.handle.net/2060/20110007883 |
著者(英) | Chi, P. J.; Le, G.; Slavin, J. A.; Strangeway, R. J. |
著者所属(英) | NASA Goddard Space Flight Center |
発行日 | 2010-06-22 |
言語 | eng |
内容記述 | Space Technology 5 (ST-5) mission is a three micro-satellite constellation deployed into a 300 x 4500 km, dawn-dusk, and sun synchronous polar orbit with 105.6deg inclination angle. Due to 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 across the dayside closed field line region at subauroral latitudes, they frequently observe strong transverse oscillations at 30-200 mHz, or in the Pe 2-3 frequency range. These Pc 2-3 waves appear as wave packets with durations in the order of 5-10 minutes. As the maximum separations of the ST-5 spacecraft are in the order of 10 minutes, 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 Pc 2- 3 band; instead, the waves appear to be the common Pc 4-5 waves associated with field line resonances. We suggest that this unique Pc 2-3 waves seen by ST-5 are in fact the Doppler-shifted Pc 4-5 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-disk orbits at proper altitudes and magnetic latitudes reveal the azimuthal characteristics of field-aligned resonances. |
NASA分類 | Astronomy |
権利 | Copyright, Distribution as joint owner in the copyright |
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