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

Abstract

Abstract. 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 Analyser 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 premidnight 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.

Rocket‐borne measurements of electron temperature and density with the Electron Retarding Potential Analyzer instrument

“…, ; Bankov et al. , ; Fang and Cheng , ] and planetary missions [ Knudsen et al , ; Hanson and Mantas , ]. However, there have been very limited attempts to obtain electron parameters using a retarding potential analyzer design [ Rajput and Garg , ].…”

Global response of the ionosphere to atmospheric tides forced from below: Comparison between COSMIC measurements and simulations by atmosphere‐ionosphere coupled model GAIA

“…As evidence of modulation in the dynamo, a WN4 structure has been observed in E × B plasma drift [ Hartman and Heelis , 2007; Kil et al , 2007, 2008; Ren et al , 2008, 2009] and in the equatorial electrojet (EEJ) [ England et al , 2006b; Lühr et al , 2008]. The satellite observations of different ionospheric and thermospheric parameters, such as: total electron content (TEC), the electron temperature, F region zonal neutral wind and neutral mass density, the ionospheric F2 layer height (h m F2), also have shown WN4 longitude structures [e.g., Lin et al , 2007a, 2007b; Lühr et al , 2007; Häusler and Lühr , 2009; Wan et al , 2008; Fejer et al , 2008; Bankov et al , 2009; Liu et al , 2009].…”

Global ionospheric response to nonmigrating DE3 and DE2 tides forced from below

“…The nonmigrating diurnal eastward propagating wave number 3 (DE3, D corresponds to diurnal tide and E to eastward propagation) signature in the ionosphere has been identified by the IMAGE satellite [ Sagawa et al , 2005; Immel et al , 2006] as WN4 longitude structure. The satellite observations of different ionospheric and thermospheric parameters, such as: total electron content (TEC), the vertical E × B plasma drift, the equatorial electrojet (EEJ), the electron temperature, F region zonal neutral wind and neutral mass density, also have shown WN4 longitude structures [e.g., England et al , 2006; Kil et al , 2007, 2008; Lin et al , 2007a, 2007b; Hartman and Heelis , 2007; Lühr et al , 2007; Häusler and Lühr , 2009; Ren et al , 2008; Wan et al , 2008; Fejer et al , 2008; Bankov et al , 2009; Liu et al , 2009].…”