Asymmetry of auroral electron precipitations and its relationship to the substorm expansion phase onset
نویسندگان
چکیده
منابع مشابه
The correlation of ULF waves and auroral intensity before, during and after substorm expansion phase onset
[1] We present case studies of the evolution of Ultra-Low Frequency (ULF) magnetic wave amplitudes and auroral intensity through the late growth phase and the expansion phase of the substorm cycle. We present strong evidence that substorm-related auroral enhancements are clearly and demonstrably linked to ULF wave amplitudes observed at the same location. In all three case studies presented, th...
متن کاملRelationship between wave-like auroral arcs and Pi2 disturbances in plasma sheet prior to substorm onset
Wave-like substorm arc features in the aurora and Pi2 magnetic disturbances observed in the near-Earth plasma sheet are frequently, and sometimes simultaneously, observed around the substorm onset time. We perform statistical analyses of the THEMIS ASI auroral observations that show wave-like bright spot structure along the arc prior to substorm onset. The azimuthal mode number values of the wa...
متن کاملRelation of the auroral substorm to the substorm current wedge
The auroral substorm is an organized sequence of events seen in the aurora near midnight. It is a manifestation of the magnetospheric substorm which is a disturbance of the magnetosphere brought about by the solar wind transfer of magnetic flux from the dayside to the tail lobes and its return through the plasma sheet to the dayside. The most dramatic feature of the auroral substorm is the sudd...
متن کاملWavelet-based ULF wave diagnosis of substorm expansion phase onset
[1] Using a discrete wavelet transform with a Meyer wavelet basis, we present a new quantitative algorithm for determining the onset time of Pi1 and Pi2 ULF waves in the nightside ionosphere with 20to 40-s resolution at substorm expansion phase onset. We validate the algorithm by comparing both the ULF wave onset time and location to the optical onset determined by the Imager for Magnetopause-t...
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 ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of Geophysical Research
سال: 2002
ISSN: 0148-0227
DOI: 10.1029/2001ja003503