WN4 effect on longitudinal distribution of different ion species in the topside ionosphere at low latitudes by means of DEMETER, DMSP-F13 and DMSP-F15 data

L.G. Bankov (1) , R. A. Heelis (2) , Michel Parrot (3) , Jean-Jacques Berthelier (4) , P.G. Marinov (5) , A.K. Vassileva (1)

1 SRI - Space Research Institute of the Bulgarian Academy of Science
2 William B. Hanson Center for Space Sciences
3 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace
4 HELIOS - LATMOS
5 Institute of Parallel Processing-BAS

Plasma probe data from DMSP-F13, DMSP-F15 and DEMETER satellites were used to examine longitudinal structures in the topside equatorial ionosphere during fall equinox conditions of 2004 year. Since the launch of DEME-TER satellite on 29 June 2004, all these satellites operate close together in the topside ionosphere. Here, data taken from Special Sensor-Ion, Electron and Scintillations (SSIES) instruments on board DMSP-F13, F15 and Instrument Anal-yser de Plasma (IAP) on DEMETER, are used. Longitudinal variations in the major ions at two altitudes (∼730 km for DEMETER and ∼840 km for DMSP) are studied to further describe the recently observed " wavenumber-four " (WN4) structures in the equatorial topside ionosphere. Different ion species H + , He + and O + have a rather complex longitudinal behavior. It is shown that WN4 is almost a regular feature in O + the density distribution over all local times covered by these satellites. In the evening local time sector, H + ions follow the O + behavior within WN4 structures up to the pre-midnight hours. Near sunrise H + and later in the daytime, He + longitudinal variations are out of phase with respect to O + ions and effectively reduce the effect of WN4 on total ion density distribution at altitudes 730–840 km. It is shown that both a WN4 E × B drift driver and local F-region winds must be considered to explain the observed ion composition variations.

Domaines: Océan, Atmosphère; Physique des plasmas [physics.plasm-ph]; Planète et Univers [physics]; Physique Atmosphérique et Océanique [physics.ao-ph]

L.G. Bankov, R. A. Heelis, Michel Parrot, Jean-Jacques Berthelier, P.G. Marinov, et al.. WN4 effect on longitudinal distribution of different ion species in the topside ionosphere at low latitudes by means of DEMETER, DMSP-F13 and DMSP-F15 data. Annales Geophysicae, 2009, 27 (7), pp.2893-2902. ⟨10.5194/angeo-27-2893-2009⟩. ⟨hal-00407574⟩