A Rocket-Borne Low-Frequency Propagation Experiment to Determine D-Region Electron Densities

Nature ◽  
1963 ◽  
Vol 200 (4907) ◽  
pp. 642-644 ◽  
Author(s):  
J. E. HALL ◽  
K. BULLOUGH
Keyword(s):  
Low Frequency ◽  
Electron Densities ◽  
D Region ◽  
Propagation Experiment

Rocket-borne equipment for an l.f. D region propagation experiment

1967 ◽  
Vol 114 (6) ◽  
pp. 703
Author(s):  
K. Bullough ◽  
A.J. Hall ◽  
J.E. Hall ◽  
R.W. Smith
Keyword(s):  
D Region ◽  
Propagation Experiment

scholarly journals Survey of electron density changes in the daytime ionosphere over the Arecibo observatory due to lightning and solar flares

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Caitano L. da Silva ◽  
Sophia D. Salazar ◽  
Christiano G. M. Brum ◽  
Pedrina Terra
Keyword(s):  
Electron Density ◽  
Solar Flares ◽  
Low Frequency ◽  
Lower Ionosphere ◽  
Weather Conditions ◽  
Optical Observations ◽  
Radio Waves ◽  
D Region ◽  
E Region ◽  
Arecibo Observatory

AbstractOptical observations of transient luminous events and remote-sensing of the lower ionosphere with low-frequency radio waves have demonstrated that thunderstorms and lightning can have substantial impacts in the nighttime ionospheric D region. However, it remains a challenge to quantify such effects in the daytime lower ionosphere. The wealth of electron density data acquired over the years by the Arecibo Observatory incoherent scatter radar (ISR) with high vertical spatial resolution (300-m in the present study), combined with its tropical location in a region of high lightning activity, indicate a potentially transformative pathway to address this issue. Through a systematic survey, we show that daytime sudden electron density changes registered by Arecibo’s ISR during thunderstorm times are on average different than the ones happening during fair weather conditions (driven by other external factors). These changes typically correspond to electron density depletions in the D and E region. The survey also shows that these disturbances are different than the ones associated with solar flares, which tend to have longer duration and most often correspond to an increase in the local electron density content.

scholarly journals Characterization of gravity waves in the lower ionosphere using very low frequency observations at Comandante Ferraz Brazilian Antarctic Station

2020 ◽  
Vol 38 (2) ◽  
pp. 385-394
Author(s):  
Emilia Correia ◽  
Luis Tiago Medeiros Raunheitte ◽  
José Valentin Bageston ◽  
Dino Enrico D'Amico
Keyword(s):  
Low Frequency ◽  
Lower Ionosphere ◽  
Drake Passage ◽  
Wave Period ◽  
Very Low Frequency ◽  
Reflection Height ◽  
D Region ◽  
Radio Signals ◽  
Sky Conditions ◽  
The Waves

Abstract. The goal of this work is to investigate the gravity wave (GW) characteristics in the low ionosphere using very low frequency (VLF) radio signals. The spatial modulations produced by the GWs affect the conditions of the electron density at reflection height of the VLF signals, which produce fluctuations of the electrical conductivity in the D region that can be detected as variations in the amplitude and phase of VLF narrowband signals. The analysis considered the VLF signal transmitted from the US Cutler, Maine (NAA) station that was received at Comandante Ferraz Brazilian Antarctic Station (EACF, 62.1∘ S, 58.4∘ W), with its great circle path crossing the Drake Passage longitudinally. The wave periods of the GWs detected in the low ionosphere are obtained using the wavelet analysis applied to the VLF amplitude. Here the VLF technique was used as a new aspect for monitoring GW activity. It was validated comparing the wave period and duration properties of one GW event observed simultaneously with a co-located airglow all-sky imager both operating at EACF. The statistical analysis of the seasonal variation of the wave periods detected using VLF technique for 2007 showed that the GW events occurred all observed days, with the waves with a period between 5 and 10 min dominating during night hours from May to September, while during daytime hours the waves with a period between 0 and 5 min are predominant the whole year and dominate all days from November to April. These results show that VLF technique is a powerful tool to obtain the wave period and duration of GW events in the low ionosphere, with the advantage of being independent of sky conditions, and it can be used during the whole day and year-round.

scholarly journals Novel Modelling Approach for Obtaining the Parameters of Low Ionosphere under Extreme Radiation in X-Spectral Range

2021 ◽  
Vol 11 (23) ◽  
pp. 11574
Author(s):  
Vladimir A. Srećković ◽  
Desanka M. Šulić ◽  
Veljko Vujčić ◽  
Zoran R. Mijić ◽  
Ljubinko M. Ignjatović
Keyword(s):  
Spectral Range ◽  
Low Frequency ◽  
Lower Ionosphere ◽  
Simple Expression ◽  
Spectral Lines ◽  
Spectral Radiation ◽  
X Ray ◽  
Reflection Height ◽  
D Region ◽  
Modelling Approach

Strong radiation from solar X-ray flares can produce increased ionization in the terrestrial D-region and change its structure. Moreover, extreme solar radiation in X-spectral range can create sudden ionospheric disturbances and can consequently affect devices on the terrain as well as signals from satellites and presumably cause numerous uncontrollable catastrophic events. One of the techniques for detection and analysis of solar flares is studying the variations in time of specific spectral lines. The aim of this work is to present our study of solar X-ray flare effects on D-region using very low-frequency radio signal measurements over a long path in parallel with the analysis of X-spectral radiation, and to obtain the atmospheric parameters (sharpness, reflection height, time delay). We introduce a novel modelling approach and give D-region coefficients needed for modelling this medium, as well as a simple expression for electron density of lower ionosphere plasmas. We provide the analysis and software on GitHub.

A follow up low frequency propagation experiment in Currituck Sound

2015 ◽  
Vol 137 (4) ◽  
pp. 2439-2439
Author(s):  
Richard D. Costley ◽  
Andrew R. McNeese ◽  
Megan S. Ballard ◽  
Kevin M. Lee ◽  
Kent K. Hathaway ◽  
...  
Keyword(s):  
Low Frequency ◽  
Currituck Sound ◽  
Propagation Experiment

scholarly journals Low-frequency ionospheric sounding with Narrow Bipolar Event lightning radio emissions: energy-reflectivity spectrum

2008 ◽  
Vol 26 (7) ◽  
pp. 1793-1803 ◽  
Author(s):  
A. R. Jacobson ◽  
R. Holzworth ◽  
X.-M. Shao
Keyword(s):  
Lightning Discharge ◽  
Low Frequency ◽  
Lower Ionosphere ◽  
Angle Of Incidence ◽  
Radio Emissions ◽  
Statistical Variation ◽  
Reflection Height ◽  
D Region ◽  
Relationship Of ◽  
The Relationship

Abstract. We analyze data on radio-reflection from the D-region of the lower ionosphere, retrieving the energy-reflection coefficient in the frequency range ~5–95 kHz. The data are the same as developed for a recent study of ionospheric-reflection height, and are based on recordings of powerful (multi-Gigawatt) radio emissions from a type of narrow (~10 μs) lightning discharge known as "Narrow Bipolar Events". The sequential appearance of first the groundwave signal, and then the ionospheric single-hop reflection signal, permits us to construct the energy-reflection ratio. We infer the energy reflection's statistical variation with solar zenith angle, angle-of-incidence, frequency, and propagation azimuth. There is also a marginally-significant response of the energy reflectivity to solar X-ray flux density. Finally, we review the relationship of our results to previous published reports.

Measurements of D-Region Electron Densities Utilizing the Partial Reflection Technique

AIAA Journal ◽  
1981 ◽  
Vol 19 (12) ◽  
pp. 1558-1561
Author(s):  
Robert O. Olsen ◽  
David L. Mott
Keyword(s):  
Electron Densities ◽  
Partial Reflection ◽  
D Region
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