Direct Determination of Wavenumbers of ULF Waves Using the Cluster Multipoint and Multicomponent Measurements - Archive ouverte HAL Accéder directement au contenu
Communication Dans Un Congrès Année : 2013

Direct Determination of Wavenumbers of ULF Waves Using the Cluster Multipoint and Multicomponent Measurements

Résumé

The wavenumber is a key parameter to understand the physics of the interactions between the electromagnetic waves and the ionized particles in space plasmas. Search-coil magnetometers and electric antennas measure time series of both magnetic and electric field fluctuations, respectively. The fleet of four Cluster spacecraft made possible to determine the full wave vector and even to differentiate the waves present at the same frequency in the spacecraft frame through various techniques: k-filtering analysis, wave telescope, phase differentiating method. However the fleet configuration (inter-spacecraft separation, tetrahedron elongation and planarity) limit the possibilities to use these techniques. From single spacecraft measurements, assumptions concerning the wave mode -and thus, concerning the physical processes- are usually required to derive the corresponding wavenumber. Using three orthogonal magnetic components and two electric antennas, it is possible to estimate n/Z where n is the refractive index and Z the transfer function of the interface between the plasma and the electric antennas. For ULF waves we assume Z=1 and we thus obtain the wavenumber. We test this hypothesis on a case where the spacecraft are in a close configuration in the distant cusp region and where we are able to apply the k-filtering analysis, too. The results obtained by multispacecraft and multicomponents analysis are close to each other and permit us to precise the value of Z. We test this procedure on several events (in various regions of the magnetosphere) in order to get more precise wave number measurements from the single spacecraft analysis. The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7-SPACE-2010-1) under grant agreement n. 284520 (MAARBLE).
Fichier non déposé

Dates et versions

hal-02860560 , version 1 (08-06-2020)

Identifiants

  • HAL Id : hal-02860560 , version 1

Citer

B. Grison, C. Philippe Escoubet, O. Santolík, Nicole Cornilleau-Wehrlin. Direct Determination of Wavenumbers of ULF Waves Using the Cluster Multipoint and Multicomponent Measurements. American Geophysical Union, Fall Meeting, Dec 2013, San Francisco, California, United States. pp.SM14B-03. ⟨hal-02860560⟩
12 Consultations
0 Téléchargements

Partager

Gmail Facebook X LinkedIn More