Multipoint investigation of the source region of storm-time chorus - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Annales Geophysicae Année : 2004

Multipoint investigation of the source region of storm-time chorus

Résumé

In this case study we investigate the source region of whistler-mode chorus located close to the geomagnetic equator at a radial distance of 4.4 Earth radii. We use measurements from the four Cluster spacecraft at separations of less than a few hundreds of km, recorded during the geomagnetic storm of 18 April 2002. The waveforms of the electric field fluctuations were obtained by the WBD instruments in the frequency range 50Hz-9.5kHz. Using these data, we calculate linear and rank correlation coefficients of the frequency averaged power-spectral density measured by the different spacecraft. Those coefficients have been recently shown to decrease with spacecraft separation distance perpendicular to the static magnetic field cchor03 with a characteristic scale length of 100km. We find this characteristic scale varying between 60 and 200km for different data intervals inside the source region. We examine possible explanations for the observed large scatter of the correlation coefficients, and we suggest a simultaneously acting effect of random positions of locations at which the individual chorus wave packets are generated. The statistical properties of the observations are approximately reproduced by a simple 2-D model of the source region, assuming a perpendicular half-width of 35km (approximately one wavelength of the whistler-mode waves) for the distribution of power radiated from individual active areas.
Fichier principal
Vignette du fichier
angeo-22-2555-2004.pdf (757.28 Ko) Télécharger le fichier
Origine : Accord explicite pour ce dépôt

Dates et versions

hal-00317519 , version 1 (18-06-2008)

Identifiants

  • HAL Id : hal-00317519 , version 1

Citer

O. Santolik, D. A. Gurnett, J. S. Pickett. Multipoint investigation of the source region of storm-time chorus. Annales Geophysicae, 2004, 22 (7), pp.2555-2563. ⟨hal-00317519⟩

Collections

INSU EGU
57 Consultations
97 Téléchargements

Partager

Gmail Facebook X LinkedIn More