www.ann-geophys.net/21/1457/2003/ doi:10.5194/angeo-21-1457-2003 © European Geosciences Union 2003 On the existence of Alfvén waves in the terrestrial foreshock 1Space & Atmospheric Physics Group, Blackett Laboratory, Imperial College, Prince Consort Rd, London SW7 2BW, UK 2CESR/ CNRS, 9, Avenue du Colonel Roche F-31028 Toulouse Cedex 4, France Abstract. The terrestrial foreshock is characterised by the existence of large amplitude ultra low frequency waves. The majority of such waves are observed to be left-handed in the spacecraft frame, but are in fact intrinsically right-handed and have been identified as fast-magnetosonic waves. More rarely observed are waves that are right-handed in the spacecraft frame. Cluster four spacecraft observations of such waves are presented and analysed using multi-spacecraft techniques; in particular the k-filtering/wave telescope technique is used. The waves are found to be left-handed and propagating sunwards in the plasma rest frame, and are, therefore, identified as Alfvénic. The convection of the waves anti-sunward in the solar wind flow causes the observed polarisation to be reversed. Generation mechanisms are discussed. Key words. Interplanetary physics (MHD waves and turbulence; planetary bow shocks) – Space plasma physics (wave particle interactions) Full Article (PDF, 422 KB) Citation: Eastwood, J. P., Balogh, A., Lucek, E. A., Mazelle, C., and Dandouras, I.: On the existence of Alfvén waves in the terrestrial foreshock, Ann. Geophys., 21, 1457-1465, doi:10.5194/angeo-21-1457-2003, 2003. Bibtex EndNote Reference Manager XML |
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