scholarly journals Compatible analysis of vertical and oblique ionospheric sounding data

1996 ◽  
Vol 39 (4) ◽  
Author(s):  
I. V. Krasheninnikov ◽  
J. C. Jodogne ◽  
L. F. Alberca
Keyword(s):  
Ray Tracing ◽  
Electron Density ◽  
Ionospheric Sounding ◽  
Small Valley

Examples are presented of the ray-tracing synthesis of multifrequency Oblique Sounding (OS) data on the Dourbes (Belgium) í Roquetes (Spain) path using electron density height profiles derived from Vertical Sounding (VS) measurements at both terminals. Comparison with the measured OS ionograms provides a means of assessing the accuracy of the VS true-height procedure POLAN. Particular attention was paid to a consideration of the E-F1 valley, that as concluded is often less deep than currently supposed, when derived using both ordinary and extraordinary components of the VS ionograms. Also, it was found that the peak of the F1 -layer should be expressed more distinctly (sometimes with a small valley between the F1 and F2 layers) though the corresponding VS ionograms may have no discontinuity in the region.

scholarly journals The synthesis of travelling ionospheric disturbance (TID) signatures in HF radar observations using ray tracing

2000 ◽  
Vol 18 (1) ◽  
pp. 56-64 ◽  
Author(s):  
A. J. Stocker ◽  
N. F. Arnold ◽  
T. B. Jones
Keyword(s):  
Ray Tracing ◽  
Electron Density ◽  
Ionospheric Disturbance ◽  
Density Perturbation ◽  
Hf Radar ◽  
Ionospheric Disturbances ◽  
F Region ◽  
Abstract Characteristic ◽  
Electron Density Perturbation ◽  
Radar Frequency

Abstract. Characteristic signatures are often observed in HF radar range-time-intensity plots when travelling ionospheric disturbances (TIDs) are present. These signatures, in particular the variation of the F-region skip distance, have been synthesised using a ray tracing model. The magnitude of the skip variation is found to be a function of the peak electron density perturbation associated with the TID and radar frequency. Examination of experimental observations leads to an estimate of the peak electron density perturbation amplitude of around 25% for those TIDs observed by the CUTLASS radar system. The advantage of using the skip variation over the radar return amplitude as an indicator of density perturbation is also discussed. An example of a dual radar frequency experiment has been given. The investigation of the effect of radar frequency on the observations will aid the optimisation of future experiments..Key words. Ionosphere (auroral ionosphere; ionosphere -atmosphere interactions; ionospheric disturbances)

scholarly journals Numerical simulation of oblique ionospheric heating by powerful radio waves

2018 ◽  
Vol 36 (3) ◽  
pp. 855-866
Author(s):  
Moran Liu ◽  
Chen Zhou ◽  
Xiang Wang ◽  
Bin Bin Ni ◽  
Zhengyu Zhao
Keyword(s):  
Ray Tracing ◽  
Electron Density ◽  
Oblique Incidence ◽  
Three Dimensional ◽  
Radio Waves ◽  
Powerful Radio ◽  
Ionospheric Electron Density ◽  
Ionospheric Heating ◽  
Tracing Algorithm ◽  
Electron Density And Temperature

<p><strong>Abstract.</strong> In this paper, we investigate the ionospheric heating by oblique incidence of powerful high-frequency (HF) radio waves using three-dimensional numerical simulations. The ionospheric electron density and temperature perturbations are examined by incorporating the ionospheric electron transport equations and ray-tracing algorithm. The energy distribution of oblique incidence heating waves in the ionosphere is calculated by the three-dimensional ray-tracing algorithm. The calculation takes into consideration the electric field of heating waves in the caustic region by the plane wave spectral integral method. The simulation results show that the ionospheric electron density and temperature can be disturbed by oblique incidence of powerful radio waves, especially in the caustic region of heating waves. The oblique ionospheric heating with wave incidence parallel and perpendicular to the geomagnetic field in the mid-latitude ionosphere is explored by simulations, results of which indicate that the ionospheric modulation is more effective when the heating wave propagates along the magnetic field line. Ionospheric density and temperature striations in the caustic region due to thermal self-focusing instability are demonstrated, as well as the time evolution of the corresponding fluctuation spectra.</p>

Correction’s method of the electron density model in ionosphere by ray tracing techniques

2015 ◽  
Vol 55 (6) ◽  
pp. 1630-1639
Author(s):  
Alessandro Settimi ◽  
Michael Pezzopane ◽  
Marco Pietrella ◽  
Carlo Scotto ◽  
Silvio Bianchi ◽  
...  
Keyword(s):  
Ray Tracing ◽  
Electron Density ◽  
Density Model ◽  
Tracing Techniques

HF ray tracing at high latitudes using measured meridional electron density distributions

Radio Science ◽  
1984 ◽  
Vol 19 (1) ◽  
pp. 359-374 ◽  
Author(s):  
J. P. Villain ◽  
R. A. Greenwald ◽  
J. F. Vickrey
Keyword(s):  
Ray Tracing ◽  
Electron Density ◽  
High Latitudes ◽  
Density Distributions

Ray Tracing over a Transequatorial Path

1972 ◽  
Vol 50 (10) ◽  
pp. 976-990
Author(s):  
N. C. Gerson
Keyword(s):  
Ray Tracing ◽  
Density Gradient ◽  
Electron Density ◽  
Time Of Day ◽  
Horizontal Gradient ◽  
Strong Electron ◽  
Trapped Mode ◽  
Electron Density Gradient ◽  
The Magnetic Field ◽  
Ray Paths

Ray tracing procedures including the magnetic field were employed in an attempt to explain the mechanism of transequatorial propagation. The analysis was based upon (a) 41 MHz backscatter soundings south from Mayaguez, Puerto Rico and (b) vertical-incidence observations from the ionosonde chain near 75 °W. The latter were converted into electron density versus true height profiles. Data from both sources obtained during the same month were utilized.The computed ray tracings show the expected effects for refraction from the F layer: skip and horizon focusing, predawn blackout (0200–0600 LST), escape of all rays launched above 18° irrespective of time of day, diurnal variation in one-hop propagation distances, etc. Some calculated rays attain TE distances (6000–11 000 km without intervening ground reflections) at 0800 LST, 1600–2000 LST and 2400 LST. Others are trapped to distances exceeding 11 000 km at 0800 LST and 1400–2400 LST. Fair agreement is found between TE observations and TE calculated ray paths. Specific hours and distances showed some correlation. Qualitatively the general features of TE seem clarified. The calculations imply that rays launched within 9° of the horizon southward across the (magnetic) equator are responsible for TE propagation. These rays are injected into an ionospheric trapped mode by a strong electron density gradient. For a ray launched at the ground to propagate to TE distances, two requirements must be satisfied: (a) vertical refractivity gradients propitious for radiowave trapping, and (b) horizontal refractivity gradients allowing injection and ejection of the ray into and out of the duct. TE concurrences near 0800 LST may arise because of the rapid strengthening of the postsunrise electron density gradient near 20° geomagnetic. This strong horizontal gradient then disappears, possibly because of an atmospheric expansion, and does not reappear until late afternoon. The trapping conditions, however, remain from about sunrise to midnight.The results imply that at the same or a higher frequency more TE would be observed if more energy was emitted at lower launch angles.

POVScript+: a program for model and data visualization using persistence of vision ray-tracing

2003 ◽  
Vol 36 (3) ◽  
pp. 944-947 ◽  
Author(s):  
T. D. Fenn ◽  
D. Ringe ◽  
G. A. Petsko
Keyword(s):  
Structural Analysis ◽  
Ray Tracing ◽  
Electron Density ◽  
Data Visualization ◽  
Visual Information ◽  
Three Dimensional ◽  
Input Output ◽  
High Quality ◽  
Rank Tensor ◽  
Volumetric Rendering

Macromolecular visualization is hampered by the fragmented set of available programs and the lack of cooperativity among them. The amount of visual information required for robust structural analysis is relatively difficult to generate and rarely allows further high-quality three-dimensional graphic rendering. Here, a modification ofMolScript[Kraulis (1991).J. Appl. Cryst.24, 946–950] is presented which contains the capability of the originalMolScript, the ability to carry out a majority of the options available in most other crystallographic visualization packages, as well as several new features of its own.POVScript+(currently version 1.62) allows anisotropic displacement ellipsoid rendering (read in as a second-rank tensor from a PDB file), electron-density polygonization (in several formats derived from a `marching tetrahedra' approach), volumetric rendering of electron density and GRASP/MSMS surface-map input/output. Finally,POVRayoutput is supported (viaa modified version ofPovScript) to generate high-quality renderings that are easily modified for any of a number of purposes (e.g.animations or altered textures).POVScript+provides a marked increase in the amount of structural and atomic detail possible, while still allowing a straightforward means of generating this information.

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.

scholarly journals Numerical synthesis of ionograms in horizontally inhomogeneous ionosphere on the basis of compound parabolic layer model

2016 ◽  
Vol 2 (3) ◽  
pp. 52-58 ◽  
Author(s):  
Олег Ларюнин ◽  
Oleg Laryunin
Keyword(s):  
Ray Tracing ◽  
Electron Density ◽  
Computer Time ◽  
Ionospheric Disturbances ◽  
Suggested Model ◽  
Layer Model ◽  
Calculation Time ◽  
Ray Paths ◽  
Parabolic Layer ◽  
Numerical Synthesis

Characteristic U-shaped traces cusps on ionograms have been identified as off-angle echoes from sloping electron density contours caused by the presence of traveling ionospheric disturbances (TIDs). Dynamics of the cusps is associated with horizontal drift of the disturbances. A potential for reducing calculation time in numerical synthesis of vertical ionograms is under discussion. Since numerical ray tracing is expensive in terms of computer time, we have developed simplified formulation for this study. The suggested model of compound parabolic layer allows us to analytically calculate ray paths. Changes in the shape of the ionogram cusp caused by varying TID characteristics are examined.

scholarly journals Design of Multifunctional Mesosphere-Ionosphere Sounding System and Preliminary Results

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2664
Author(s):  
Tongxin Liu ◽  
Guobin Yang ◽  
Zhengyu Zhao ◽  
Yi Liu ◽  
Chen Zhou ◽  
...  
Keyword(s):  
Electron Density ◽  
Pulse Compression ◽  
Middle Atmosphere ◽  
Electron Density Profile ◽  
System Structure ◽  
Coupling Mechanism ◽  
Antenna Structure ◽  
Miniaturized Antenna ◽  
Ionospheric Sounding ◽  
Mf Radar

This paper describes a novel sounding system for which the functions of the medium frequency (MF) radar and the ionosonde are integrated on the same hardware platform and antenna structure, namely the middle atmosphere-ionosphere (MAI) system. Unlike the common MF radar, MAI system adopts the pseudo-random (PRN) phase-coded modulation technology, which breaks the limitation of the traditional monopulse mode. Through the pulse compression, only a small peak power is needed to achieve the signal-to-noise ratio (SNR) requirement. The excellent anti-jamming performance is also very suitable for the ionospheric sounding. One transmitting and six receiving modes are adopted for the MF sounding. While neglecting the structure of the T/R switches, the coupling interference between the transmitter and the receiver may also be avoided. Moreover, by employing a miniaturized antenna array composed of progressive-wave antennas for the MF receiving and ionospheric sounding, the MAI system takes account of the requirements of the inversion algorithms of MF radar and the large bandwidth need for the ionospheric sounding concurrently. Such an antenna structure can also greatly simplify the system structure and minimize the difficulty of deployment. The experiments verified the availability of the system scheme and its engineering application significance. Through further analysis of the sounding data, the wind field of the mesosphere, the electron density of D layer and electron density profile from layers E to F were obtained at the identical location. The capability of MAI system can play an important role in studying the interaction and coupling mechanism between the mesosphere and ionosphere.

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