HR: 1340h
AN: SH53A-1260    [Abstracts]
TI: Generation of Downshifted Oscillations in the Electron Foreshock: A Loss-Cone Instability
AU: Lobzin, V
EM: vlobzine@cnrs-orleans.fr
AF: LPCE/CNRS-University of Orleans, 3A Avenue de la Recherche Scientifique, Orleans, 45071 France
AU: * Krasnoselskikh, V
EM: vkrasnos@cnrs-orleans.fr
AF: LPCE/CNRS-University of Orleans, 3A Avenue de la Recherche Scientifique, Orleans, 45071 France
AU: Schwartz, S
EM: s.schwartz@imperial.ac.uk
AF: Space and Atmospheric Physics, The Blackett Laboratory, Imperial College London, Imperial College London, London SW7 2AZ, London, SW7 2AZ United Kingdom
AU: Lefebvre, B
EM: b.lefebvre@imperial.ac.uk
AF: Space and Atmospheric Physics, The Blackett Laboratory, Imperial College London, Imperial College London, London SW7 2AZ, London, SW7 2AZ United Kingdom
AU: Cairns, I
EM: cairns@physics.usyd.edu.au
AF: School of Physics, University of Sydney, University of Sydney, Sydney NSW 2006, Sydney, 2006 Australia
AU: Decreau, P
EM: pdecreau@cnrs-orleans.fr
AF: LPCE/CNRS-University of Orleans, 3A Avenue de la Recherche Scientifique, Orleans, 45071 France
AU: Fazakerley, A
EM: anf@mssl.ucl.ac.uk
AF: Mullard SSL, University College London, Holmbury St. Mary, Dorking, Surrey, RH5 6NT, Surrey, RH5 6NT United Kingdom
AU: Dunlop, M
EM: m.dunlop@ic.ac.uk
AF: SSD, CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, Oxfordshire, OX11 0QX United Kingdom
AB: 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. Both characteristic energies and pitch angle of the loss cone vary considerably across the foreshock. Deep within foreshock the loss-cone feature is formed by suprathermal electrons with energies 15-45 eV and pitch angles 130-150 deg 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 instability of the beam mode as previously suggested. The possibility that the observed oscillations are produced due to loss-cone instability of electron sound mode is also discussed. We discuss also the role such instabilities can play in astrophysical shocks.
DE: 2154 Planetary bow shocks
DE: 2159 Plasma waves and turbulence
DE: 2164 Solar wind plasma
DE: 2471 Plasma waves and instabilities (2772)
SC: SPA-Solar and Heliospheric Physics [SH]
MN: Fall Meeting 2005