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Generation of downshifted oscillations in the electron foreshock: A loss‐cone instability
Author(s) -
Lobzin V. V.,
Krasnoselskikh V. V.,
Schwartz S. J.,
Cairns Iver,
Lefebvre B.,
Décréau P.,
Fazakerley A.
Publication year - 2005
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 - 10.1029/2005gl023563
Subject(s) - instability , foreshock , physics , electron , bow shock (aerodynamics) , shock (circulatory) , cyclotron , plasma , geophysics , computational physics , shock wave , geology , mechanics , seismology , nuclear physics , aftershock , medicine
Measurements performed aboard Cluster spacecraft near Earth's bow shock on 24 January 2001 provide convincing evidence of a loss‐cone feature within the electron foreshock region. This feature is formed by suprathermal electrons with energies 15–45 eV and pitch angles 130°–150° and is always accompanied by electrostatic waves with frequencies well below the local plasma frequency. An instability analysis shows that these downshifted oscillations can result from a loss‐cone instability of electron cyclotron modes rather than from the beam instability as previously suggested.