Open AccessA statistical study of Pc3–Pc5 magnetic pulsations observed by the AMPTE/Ion Release Module satellite
Author(s) -
Lessard M. R.,
Hudson M. K.,
Lühr H.
Publication year - 1999
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/1998ja900116
Subject(s) - physics , magnetopause , ring current , substorm , magnetosphere , field line , geophysics , geomagnetic storm , computational physics , satellite , storm , harmonic , geosynchronous orbit , magnetic field , earth's magnetic field , meteorology , quantum mechanics , astronomy
Magnetic field data from the Active Magnetospheric Particle Tracer Explorers/Ion Release Module satellite are used to complete a statistical study yielding occurrence rates of a number of different types of pulsations. Two hour panels of dynamic spectra and detrended line plots were inspected to determine occurrence rates over all local times from L = 6 to L = 20. Event types include fundamental field line resonances, harmonic resonances, storm time pulsations, and signatures of bursty bulk flows and fast flows. However, we also include observations of Pc3 compressional pulsations and note their association with harmonic events. Likewise, we include high‐frequency events (40–70 mHz) and show a relation to storm time pulsations. On the basis of the occurrence distributions, we are able to make a number of conclusions. We determine that the excitation source of fundamental resonances is likely band limited from 3 to 10 mHz and that harmonic resonances are at least sometimes associated with compressional Pc3 pulsations. Storm time pulsations, compressional in nature, are sometimes associated with relatively high frequency transverse events and often occur in regions very close to the magnetopause. On the basis of other works that associate these pulsations with instabilities in the partial ring current, we suggest that particles that form the partial ring current may extend to the magnetopause during storms and substorms. Finally, we note that bursty bulk flows and fast flows in general have a magnetic signature that is predominantly compressional, and we discuss the relevance this may have regarding substorm dipolarization.