scholarly journals Interpretation of oblique-incidence ionograms under the assumption of a spherically stratified ionosphere

2015 ◽  
Vol 1 (4) ◽  
pp. 66-71
Author(s):  
Олег Ларюнин ◽  
Oleg Laryunin ◽  
Алексей Подлесный ◽  
Aleksey Podlesnyi ◽  
Олег Романовский ◽  
...  
Keyword(s):  
Ray Tracing ◽  
Oblique Incidence ◽  
Stratified Medium ◽  
Classical Type ◽  
Height Profile ◽  
Middle Point ◽  
Density Profiles ◽  
Maximum Usable Frequency ◽  
Nose Shape ◽  
Electron Density Profiles

Oblique sounding ionograms show that an ionogram trace can be of nose shape with typical multipath for which the maximum corresponds to maximum usable frequency. However, ionograms obtained from sounding at short paths are of classical type and do not differ from vertical sounding ionograms in appearance. On the basis of ray tracing in isotropic medium we examined changes in ionogram structure when varying the ground range. It is shown that in a stratified medium, multipath can take place at any nonzero ground range though at short paths, to resolve multipathing in an experiment seems to be impossible. Some possibilities for using the assumption of sphe-rically stratified ionosphere when sounding at long radio paths (of the order of few thousand kilometers) are also under consideration. We compared the distance-frequency characteristics (DFC) produced for horizontally-nonuniform ionosphere defined along the path by IRI-2012 model, as well as for spherical-stratified ionosphere for which the height profile does not depend on horizontal coordinate and agrees with IRI-2012 profile in the middle point of the path. Although the electron density profiles exhibit significant variations along the path, DFCs agree with each other up to fraction of the percent. In this case, the form of the ionogram practically in everything is defined by the vicinity of radio path middle point.

scholarly journals Mid-point electron density profiles from oblique ionograms

1996 ◽  
Vol 39 (4) ◽  
Author(s):  
X. Huang ◽  
B. W. Reinisch ◽  
W. S. Kuklinski
Keyword(s):  
Ray Tracing ◽  
Electron Density ◽  
Efficient Technique ◽  
Computationally Efficient ◽  
Density Profiles ◽  
Cpu Time ◽  
Electron Density Profiles

A computationally efficient technique for the inversion of oblique ionograms into mid-point electron density profiles is described. The profile is given as the sum of quasi-parabolic functions suitable for ray tracing. The CPU time for a 486 desk top computer is 30 s.

Thickness parameters in the empirical modeling of bottomside electron density profiles

2021 ◽  
Author(s):  
S.M. Radicella ◽  
K. Alazo-Cuartas ◽  
Y. Migoya-Orué ◽  
A. Kashcheyev
Keyword(s):  
Electron Density ◽  
Empirical Modeling ◽  
Density Profiles ◽  
Electron Density Profiles

Electron density profiles above the F-layer

1973 ◽  
Vol 21 (9) ◽  
pp. 1581-1586
Author(s):  
Michael Anastassiadis ◽  
Georges Moraitis ◽  
Dimitris Matsoukas
Keyword(s):  
Electron Density ◽  
Density Profiles ◽  
Electron Density Profiles

scholarly journals Ionospheric assimilation techniques for ARGOS Low-Resolution Airglow and Aurora Spectrograph (LORAAS) tomographically reconstructed equatorial electron density profiles

Radio Science ◽  
2004 ◽  
Vol 39 (1) ◽  
pp. n/a-n/a ◽  
Author(s):  
J. J. Sojka ◽  
J. V. Eccles ◽  
R. W. Schunk ◽  
S. McDonald ◽  
S. Thonnard ◽  
...  
Keyword(s):  
Electron Density ◽  
Low Resolution ◽  
Density Profiles ◽  
Electron Density Profiles

A complete solar cycle (2006–2016) studies of scale heights derived using COSMIC radio occultation retrieved electron density profiles

2019 ◽  
Vol 182 ◽  
pp. 101-118 ◽  
Author(s):  
G. Uma ◽  
P.S. Brahmanandam ◽  
S. Tulasi Ram ◽  
K.-H. Wu ◽  
Y.H. Chu
Keyword(s):  
Solar Cycle ◽  
Electron Density ◽  
Radio Occultation ◽  
Cosmic Radio ◽  
Density Profiles ◽  
Electron Density Profiles

scholarly journals Case study of the mesospheric and lower thermospheric effects of solar X-ray flares: coupled ion-neutral modelling and comparison with EISCAT and riometer measurements

2008 ◽  
Vol 26 (8) ◽  
pp. 2311-2321 ◽  
Author(s):  
C.-F. Enell ◽  
P. T. Verronen ◽  
M. J. Beharrell ◽  
J. P. Vierinen ◽  
A. Kero ◽  
...  
Keyword(s):  
Solar Proton ◽  
Spectral Irradiance ◽  
Cluster Ions ◽  
Ion Chemistry ◽  
Density Profiles ◽  
X Ray ◽  
Noise Absorption ◽  
D Region ◽  
Electron Density Profiles ◽  
Cosmic Noise

Abstract. Two case studies of upper mesospheric and lower thermospheric (UMLT) high-latitude effects of solar X-ray flares are presented. Sodankylä Ion-neutral Chemistry Model (SIC) electron density profiles agree with D-region EISCAT and riometer observations, provided that the profiles of the most variable ionisable component, nitric oxide, are adjusted to compensate for NOx production during preceding geomagnetically active periods. For the M6-class flare of 27 April 2006, following a quiet period, the agreement with cosmic noise absorption observed by the Sodankylä riometers was within reasonable limits without adjustment of the [NO] profile. For the major (X17-class) event of 28 October 2003, following high auroral activity and solar proton events, the NO concentration had to be increased up to on the order of 108 cm−3 at the D-region minimum. Thus [NO] can in principle be measured by combining SIC with observations, if the solar spectral irradiance and particle precipitation are adequately known. As the two case events were short and modelled for high latitudes, the resulting neutral chemical changes are insignificant. However, changes in the model ion chemistry occur, including enhancements of water cluster ions.

Dynamical movements of electron density profiles in spherical tokamak merging processes

2003 ◽  
Vol 145 (2) ◽  
pp. 42-49
Author(s):  
Hitoshi Hayashiya ◽  
Makoto Katsurai
Keyword(s):  
Electron Density ◽  
Spherical Tokamak ◽  
Density Profiles ◽  
Electron Density Profiles

scholarly journals Variations of topside ionospheric scale heights over Millstone Hill during the 30-day incoherent scatter radar experiment

2007 ◽  
Vol 25 (9) ◽  
pp. 2019-2027 ◽  
Author(s):  
L. Liu ◽  
W. Wan ◽  
M.-L. Zhang ◽  
B. Ning ◽  
S.-R. Zhang ◽  
...  
Keyword(s):  
Electron Density ◽  
Thermal Structure ◽  
Plasma Temperature ◽  
Scale Height ◽  
Incoherent Scatter Radar ◽  
Density Profiles ◽  
Incoherent Scatter ◽  
Scatter Radar ◽  
Vertical Scale ◽  
Electron Density Profiles

Abstract. A 30-day incoherent scatter radar (ISR) experiment was conducted at Millstone Hill (288.5° E, 42.6° N) from 4 October to 4 November 2002. The altitude profiles of electron density Ne, ion and electron temperature (Ti and Te), and line-of-sight velocity during this experiment were processed to deduce the topside plasma scale height Hp, vertical scale height VSH, Chapman scale height Hm, ion velocity, and the relative altitude gradient of plasma temperature (dTp/dh)/Tp, as well as the F2 layer electron density (NmF2) and height (hmF2). These data are analyzed to explore the variations of the ionosphere over Millstone Hill under geomagnetically quiet and disturbed conditions. Results show that ionospheric parameters generally follow their median behavior under geomagnetically quiet conditions, while the main feature of the scale heights, as well as other parameters, deviated significantly from their median behaviors under disturbed conditions. The enhanced variability of ionospheric scale heights during the storm-times suggests that the geomagnetic activity has a major impact on the behavior of ionospheric scale heights, as well as the shape of the topside electron density profiles. Over Millstone Hill, the diurnal behaviors of the median VSH and Hm are very similar to each other and are not so tightly correlated with that of the plasma scale height Hp or the plasma temperature. The present study confirms the sensitivity of the ionospheric scale heights over Millstone Hill to thermal structure and dynamics. The values of VSH/Hp tend to decrease as (dTp/dh)/Tp becomes larger or the dynamic processes become enhanced.

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