HR: 0800h
AN: SM51C-0386    [Abstracts]
TI: Statistical Survey of the Properties of Gyrating Ions in the Earth's Foreshock
AU: * Mazelle, C
EM: mazelle@cesr.fr
AF: Centre d'Etude Spatiale des Rayonnements, 9, Avenue du Colonel Roche, Toulouse, 31400 France
AU: Meziane, K
EM: karim@unb.ca
AF: Physics Department, University of New Brunswick, Fredericton, NB E3B5A3 Canada
AU: Wilber, M
EM: wilber@ssl.berkeley.edu
AF: Space Sciences Laboratory Sciences Laboratory, University of California, Berkeley, CA 94720 United States
AU: LeQu\'{e}au, D
EM: lequeau@obs-mip.fr
AF: Centre d'Etude Spatiale des Rayonnements, 9, Avenue du Colonel Roche, Toulouse, 31400 France
AU: Eastwood, J P
EM: jeastwood@lepvax.gsfc.nasa.gov
AF: Laboratory for Extraterrestrial Physics, NASA Goddard Space Flight Center, Greenbelt, MD 20771 United States
AU: Parks, G K
EM: parks@ssl.berkeley.edu
AF: Space Sciences Laboratory Sciences Laboratory, University of California, Berkeley, CA 94720 United States
AU: R_`{e}me, H
EM: reme@cesr.fr
AF: Centre d'Etude Spatiale des Rayonnements, 9, Avenue du Colonel Roche, Toulouse, 31400 France
AB: Gyrating backstreaming ions displaying gyrophase-bunching around the local magnetic field are frequently observed upstream of the Earth's bow shock. These ions are always associated with quasi-monochromatic right-hand mode low-frequency waves. Previously some case studies have been made to explain these ion features. The proposed mechanism is either a non-local production by a specular reflexion at the bow shock itself or a local nonlinear wave- particle interaction involving initially field-aligned beam ions and the waves. From a much larger data set now available, the physical properties of the gyrophase-bunched ions can be determined by sophisticated mathematical methods allowing to fit distributions without the maxwellian assumption. These derived properties are used to test and discriminate the two possible production mechanisms proposed. A strong emphasis is put on the association with field-aligned beams given from multi-spacecraft observations by Cluster.
DE: 7839 Nonlinear phenomena
DE: 7867 Wave/particle interactions
DE: 2116 Energetic particles, planetary
DE: 2134 Interplanetary magnetic fields
DE: 2154 Planetary bow shocks
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting