A measurement of positive ion density in the night-time F-region

1965 ◽  
Vol 13 (1) ◽  
pp. 1-8 ◽  
Author(s):  
K. Norman ◽  
A.P. Willmore
Keyword(s):  
Night Time ◽  
Ion Density ◽  
F Region ◽  
Positive Ion

scholarly journals Observations of AGW/TID propagation across the polar cap: a case study

2011 ◽  
Vol 29 (8) ◽  
pp. 1355-1363 ◽  
Author(s):  
H. T. Cai ◽  
F. Yin ◽  
S. Y. Ma ◽  
I. W. McCrea
Keyword(s):  
Large Scale ◽  
Source Region ◽  
Polar Cap ◽  
Night Time ◽  
F Region ◽  
Atmospheric Disturbances ◽  
Geomagnetic Pole ◽  
Ionization Waves ◽  
North Polar ◽  
Propagation Properties

Abstract. In this paper, we present observational evidence for the trans-polar propagation of large-scale Traveling Ionospheric Disturbances (TIDs) from their nightside source region to the dayside. On 13 February 2001, the 32 m dish of EISCAT Svalbard Radar (ESR) was directing toward the geomagnetic pole at low elevation (30°) during the interval 06:00–12:00 UT (MLT ≈ UT + 3 h), providing an excellent opportunity to monitor the ionosphere F-region over the polar cap. The TIDs were first detected by the ESR over the dayside north polar cap, propagating equatorward, and were subsequently seen by the mainland UHF radar at auroral latitudes around geomagnetic local noon. The propagation properties of the observed ionization waves suggest the presence of a moderately large-scale TIDs, propagating across the northern polar cap from the night-time auroral source during substorm conditions. Our results agree with the theoretical simulations by Balthazor and Moffett (1999) in which poleward-propagating large-scale traveling atmospheric disturbances were found to be self-consistently driven by enhancements in auroral heating.

scholarly journals 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

2009 ◽  
Vol 27 (7) ◽  
pp. 2893-2902 ◽  
Author(s):  
L. Bankov ◽  
R. Heelis ◽  
M. Parrot ◽  
J.-J. Berthelier ◽  
P. Marinov ◽  
...  
Keyword(s):  
Density Distribution ◽  
Major Ions ◽  
Local Times ◽  
Longitudinal Distribution ◽  
Topside Ionosphere ◽  
Regular Feature ◽  
Ion Density ◽  
F Region ◽  
Longitudinal Variations ◽  
Ion Species

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 DEMETER 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 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.

scholarly journals The dependence of plasma density in the topside ionosphere on the solar activity level

2007 ◽  
Vol 25 (6) ◽  
pp. 1337-1343 ◽  
Author(s):  
L. Liu ◽  
W. Wan ◽  
X. Yue ◽  
B. Zhao ◽  
B. Ning ◽  
...  
Keyword(s):  
Solar Activity ◽  
Plasma Density ◽  
Rate Of Change ◽  
Activity Level ◽  
Nonlinear Dependence ◽  
High Solar Activity ◽  
Topside Ionosphere ◽  
Ion Density ◽  
Solar Activity Level ◽  
F Region

Abstract. In this paper, the ten-year (1996–2005) total ion density Ni measurements from the Defense Meteorological Satellite Program (DMSP) spacecraft in the morning and evening (09:30 and 21:30 LT) sectors have been analyzed to explore the dependence of plasma densities in the topside ionosphere at middle and low latitudes on the solar activity level. Results indicate that there is a strong solar activity dependence of DMSP Ni at 848 km altitude, which has latitudinal and seasonal features. The plasma density in the topside ionosphere has an approximately linear dependence on daily F107 and a strongly nonlinear dependence on SEM/SOHO EUV, such that the change rate of Ni becomes greater with increasing solar EUV. This is quite different from the dependence of Ni near the F-Region peak (NmF2), at which the rate of change of NmF2 decreases with increasing solar EUV. The rate of change of Ni at the DMSP altitude is greatest in the latitude range where Ni is greatest during high solar activity. We suggest that this greater rate of change (or amplification effect) of Ni at the DMSP altitude is mainly a consequence of the solar activity variations of the topside scale height. The changes in the height of the F-Region peak (hmF2) and the density NmF2 play a secondary role.

Photoionization rates in the night-time E- and F-region ionosphere∗

1980 ◽  
Vol 28 (11) ◽  
pp. 1027-1033 ◽  
Author(s):  
D.F. Strobel ◽  
C.B. Opal ◽  
R.R. Meier
Keyword(s):  
Night Time ◽  
F Region
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