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Modulated electron‐acoustic waves in auroral density cavities: FAST observations
Author(s) -
Pottelette R.,
Ergun R. E.,
Treumann R. A.,
Berthomier M.,
Carlson C. W.,
McFadden J. P.,
Roth I.
Publication year - 1999
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/1999gl900462
Subject(s) - physics , envelope (radar) , electron , amplitude , acceleration , acoustic wave , spacecraft , ion acoustic wave , wave packet , magnetic field , computational physics , geophysics , atomic physics , optics , astronomy , classical mechanics , telecommunications , radar , quantum mechanics , computer science
We report on FAST observations of large amplitude (up to 500 mV m −1 ) envelope solitary waves at the edges of the AKR source region. These edges are characterized by the presence of two electron populations: a dominant hot (∼keV) component and a minority cold (<60 eV) component. The nonlinear waves are recorded when the spacecraft passes the base of the parallel auroral acceleration region. They form intense packets of electron acoustic waves. The modulation is due to ion acoustic waves. These structures are electrostatic and propagate along the magnetic field at speeds of a few 100 km s −1 . They may play a crucial role in the acceleration processes taking place in these regions.