Estimation of the characteristic energy of electron precipitation - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Annales Geophysicae Année : 2002

Estimation of the characteristic energy of electron precipitation

Résumé

Data from simultaneous observations (on 13 February 1996, 9 November 1998, and 12 February 1999) with the IRIS, DASI and EISCAT systems are employed in the study of the energy distribution of the electron precipitation during substorm activity. The estimation of the characteristic energy of the electron precipitation over the common field of view of IRIS and DASI is discussed. In particular, we look closely at the physical basis of the correspondence between the characteristic energy, the flux-averaged energy, as defined below, and the logarithm of the ratio of the green-light intensity to the square of absorption. This study expands and corrects results presented in the paper by Kosch et al. (2001). It is noticed, moreover, that acceleration associated with diffusion processes in the magnetosphere long before precipitation may be controlling the shape of the energy spectrum. We propose and test a "mixed" distribution for the energy-flux spectrum, exponential at the lower energies and Maxwellian or modified power-law at the higher energies, with a threshold energy separating these two regimes. The energy-flux spectrum at Tromsø, in the 1?320 keV range, is derived from EISCAT electron density profiles in the 70?140 km altitude range and is applied in the "calibration" of the optical intensity and absorption distributions, in order to extrapolate the flux and characteristic energy maps.
Fichier principal
Vignette du fichier
angeo-20-1349-2002.pdf (1.59 Mo) Télécharger le fichier
Origine : Accord explicite pour ce dépôt
Loading...

Dates et versions

hal-00317128 , version 1 (18-06-2008)

Identifiants

  • HAL Id : hal-00317128 , version 1

Citer

C. F. del Pozo, M. J. Kosch, F. Honary. Estimation of the characteristic energy of electron precipitation. Annales Geophysicae, 2002, 20 (9), pp.1349-1359. ⟨hal-00317128⟩

Collections

INSU EGU
42 Consultations
51 Téléchargements

Partager

Gmail Facebook X LinkedIn More