Characteristics of magnetospherically reflected chorus waves observed by Cluster. - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Annales Geophysicae Année : 2004

Characteristics of magnetospherically reflected chorus waves observed by Cluster.

Résumé

Chorus emissions are often observed by the STAFF spectrum analyser on board the 4 satellites of CLUSTER. This instrument provides the cross spectral matrix of three magnetic and two electric field components. Dedicated software processes this spectral matrix in order to determine the propagation characteristic of these chorus waves. Measurements of the parallel component of the Poynting vector around the magnetic equator indicate that the chorus waves propagate away from this region which is considered as the source area of these emissions. This is valid for the most intense waves observed on the magnetic and electric power spectrograms. But it has also been observed that lower intensity waves propagate toward the equator at the same frequency. Using the wave normal directions of these waves, a ray tracing study has shown that the waves have suffered a Lower Hybrid Resonance (LHR) reflection at low altitudes and now return to the equator at a different location with a lower intensity. The paper presents other similar events when WBD data are simultaneously recorded. The WBD experiment provides a much better time resolution and allows one to check the structure of the returning waves. It is observed that these waves have still a high degree of polarization, even if they started to lose the coherent structure of the chorus elements. They reach the equator with a small wave normal angle which is more efficient for a further amplification. It is explained that these emissions could be a source of hiss.
Fichier principal
Vignette du fichier
angeo-22-2597-2004.pdf (3.9 Mo) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte
Loading...

Dates et versions

hal-00153166 , version 1 (04-01-2016)

Identifiants

Citer

Michel Parrot, O. Santolik, D. Gurnett, J.S. Pickett, N. Cornilleau-Wehrlin. Characteristics of magnetospherically reflected chorus waves observed by Cluster.. Annales Geophysicae, 2004, 22 (7), pp.2597-2606. ⟨10.5194/angeo-22-2597-2004⟩. ⟨hal-00153166⟩
244 Consultations
128 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More