Distinction between auroral substorm onset and traditional ground magnetic onset signatures
نویسندگان
چکیده
منابع مشابه
Relations between multiple auroral streamers, preonset thin arc formation, and substorm auroral onset
[1] Recent ground‐based imager observations have provided evidence of precursor auroral activity leading to substorm auroral onset, where the precursor is initiated by a poleward boundary intensification (PBI) followed by an auroral streamer moving equatorward toward the onset latitude leading to substorm auroral onset. However, since many streamers do not lead to substorms, the question arises...
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Rapid fading of auroral activity a few minutes before substorm breakup has earlier been analyzed in case-studies. Here we report on a study in which all-sky camera (ASC) and magnetic data over 3 years were examined to ®nd breakups that were accompanied by a preceding fading. To illustrate typical features of the fading eect we analyze three events in detail and discuss seven other events to ®n...
متن کاملAKR breakup and auroral particle acceleration at substorm onset
[1] The dynamical behavior of auroral kilometric radiation (AKR) is investigated in connection with auroral particle acceleration at substorm onsets using high-time-resolution wave spectrograms provided by Polar/PWI electric field observations. AKR develops explosively at altitudes above a preexisting low-altitude AKR source at substorm onsets. This ‘‘AKR breakup’’ suggests an abrupt formation ...
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[1] A superposed epoch analysis of 100–300 substorms is performed to determine the median size and shape of the substorm-associated VLF chorus, magnetic bay, and Pi2 pulsation burst observed at the near-auroral Halley research station, Antarctica, and at the midlatitude Faraday station at three different local times (2230, 2330, 0130 MLT). The spatial and temporal properties of the magnetic bay...
متن کاملVertical evolution of auroral acceleration at substorm onset
This study describes the onset process of auroral substorms in connection with the vertical evolution of auroral particle acceleration, on the basis of auroral kilometric radiation (AKR) dynamics. We show that the auroral acceleration process at substorm onset basically consists of two stages: (1) appearance/intensification of a low-altitude acceleration region at 4000–5000 km accompanied by in...
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ژورنال
عنوان ژورنال: Journal of Geophysical Research: Space Physics
سال: 2013
ISSN: 2169-9380
DOI: 10.1002/jgra.50384