Systematic analysis of occurrence of equatorial noise emissions using 10 years of data from the Cluster mission - CNRS - Centre national de la recherche scientifique Accéder directement au contenu
Article Dans Une Revue Journal of Geophysical Research Space Physics Année : 2015

Systematic analysis of occurrence of equatorial noise emissions using 10 years of data from the Cluster mission

Résumé

We report results of a systematic analysis of equatorial noise (EN) emissions which are also known as fast magnetosonic waves. EN occurs in the vicinity of the geomagnetic equator at frequencies between the local proton cyclotron frequency and the lower hybrid frequency. Our analysis is based on the data collected by the Spatio-Temporal Analysis of Field Fluctuations-Spectrum Analyzer instruments on board the four Cluster spacecraft. The data set covers the period from January 2001 to December 2010. We have developed selection criteria for the visual identification of these emissions, and we have compiled a list of more than 2000 events identified during the analyzed time period. The evolution of the Cluster orbit enables us to investigate a large range of McIlwain's parameter from about L˜1.1 to L˜10. We demonstrate that EN can occur at almost all analyzed L shells. However, the occurrence rate is very low (<6%) at L shells below L=2.5 and above L=8.5. EN mostly occurs between L=3 and L=5.5, and within 7° of the geomagnetic equator, reaching 40% occurrence rate. This rate further increases to more than 60% under geomagnetically disturbed conditions. Analysis of occurrence rates as a function of magnetic local time (MLT) shows strong variations outside of the plasmasphere (with a peak around 15 MLT), while the occurrence rate inside the plasmasphere is almost independent on MLT. This is consistent with the hypothesis that EN is generated in the afternoon sector of the plasmapause region and propagates both inward and outward.
Fichier principal
Vignette du fichier
2014JA020268.pdf (2.46 Mo) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte

Dates et versions

hal-01551995 , version 1 (12-11-2021)

Licence

Copyright (Tous droits réservés)

Identifiants

Citer

Z. Hrbackova, O. Santolík, F. Nemec, E. Macusova, Nicole Cornilleau-Wehrlin. Systematic analysis of occurrence of equatorial noise emissions using 10 years of data from the Cluster mission. Journal of Geophysical Research Space Physics, 2015, 120, pp.1007-1021. ⟨10.1002/2014JA020268⟩. ⟨hal-01551995⟩
254 Consultations
23 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More