Quasiperiodic Emissions and Related Particle Precipitation Bursts Observed by the DEMETER Spacecraft - INSU - Institut national des sciences de l'Univers Accéder directement au contenu
Article Dans Une Revue Journal of Geophysical Research Space Physics Année : 2021

Quasiperiodic Emissions and Related Particle Precipitation Bursts Observed by the DEMETER Spacecraft

Résumé

Electromagnetic waves observed in the inner magnetosphere at frequencies between about 0.5 and 4 kHz sometimes exhibit a quasiperiodic (QP) time modulation of the wave intensity with modulation periods from tens of seconds up to a few minutes. Such waves are typically termed QP emissions and their origin is still not fully understood. We use a large set of more than 2,000 of these events identified in the low-altitude DEMETER spacecraft data to check for energetic electron flux variations matching the individual QP wave elements. Altogether, 7 such events are identified and their detailed analysis is performed. Energetic electron fluxes are found to be modulated primarily at energies lower than about 250 keV. While the waves may propagate unducted across L-shells, the energetic particles follow magnetic field lines from the interaction region down to the observation point. This is used to estimate the locations of anticipated generation regions to L-shells between about 4 and 6, and the respective source radial dimensions to about 0.6-1.2 Earth radii. The frequencies of the events are confined below half of the equatorial electron gyrofrequency in the determined source regions. Finally, it is shown that individual QP elements exhibit a fine inner structure corresponding to the wave bouncing between the hemispheres.
Fichier principal
Vignette du fichier
2021JA029621.pdf (729.58 Ko) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)

Dates et versions

insu-03357774 , version 1 (29-09-2021)

Licence

Paternité

Identifiants

Citer

František Němec, M. Hajoš, Michel Parrot, O. Santolík. Quasiperiodic Emissions and Related Particle Precipitation Bursts Observed by the DEMETER Spacecraft. Journal of Geophysical Research Space Physics, 2021, 126 (10), pp.e2021JA029621. ⟨10.1029/2021JA029621⟩. ⟨insu-03357774⟩
48 Consultations
53 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More