Generation of downshifted oscillations in the electron foreshock: A loss-cone instability

V. Lobzin (1) , Vladimir Krasnoselskikh (1) , S. Schwartz (2) , Iver Cairns (3) , B. Lefebvre (4) , Pierrette Décréau (1) , A. Fazakerley (5)

1 LPCE - Laboratoire de physique et chimie de l'environnement
2 Thales Research and Technology [Palaiseau]
3 The University of Sydney
4 Imperial College London
5 MSSL - Mullard Space Science Laboratory

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 degrees - 150 degrees 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.

Domaines: Géophysique [physics.geo-ph]

V. Lobzin, Vladimir Krasnoselskikh, S. Schwartz, Iver Cairns, B. Lefebvre, et al.. Generation of downshifted oscillations in the electron foreshock: A loss-cone instability. Geophysical Research Letters, 2005, 32 (18), pp.L18101. ⟨10.1029/2005GL023563⟩. ⟨insu-02873854⟩