Sunset-sunrise characteristics of sporadic layers of ionization in the lower ionosphere observed by the method of resonance scattering of radio waves from artificial periodic inhomogeneities of the ionospheric plasma

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.

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Variations of ozone microwave emission from the mesosphere at heating a lower ionosphere powerful HF radio waves

2012 6th European Conference on Antennas and Propagation (EUCAP) ◽

10.1109/eucap.2012.6206516 ◽

2012 ◽

Author(s):

Yuri Kulikov ◽

Vladimir Frolov

Keyword(s):

Lower Ionosphere ◽

Microwave Emission ◽

Radio Waves

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HF-Induced Modifications of the Electron Density Profile in the Earth’s Ionosphere Using the Pump Frequencies near the Fourth Electron Gyroharmonic

Remote Sensing ◽

10.3390/rs13234895 ◽

2021 ◽

Vol 13 (23) ◽

pp. 4895

Author(s):

Alexey V. Shindin ◽

Evgeny N. Sergeev ◽

Savely M. Grach ◽

Gennady M. Milikh ◽

Paul Bernhardt ◽

...

Keyword(s):

Density Profile ◽

Ionospheric Plasma ◽

Pump Wave ◽

Electromagnetic Emission ◽

Electron Density Profile ◽

Radio Waves ◽

F Region ◽

Plasma Density Profile ◽

Hybrid Region ◽

Hf Heating

We discuss results on plasma density profile modifications in the F-region ionosphere that are caused by HF heating with the frequency f0 in the range [(−150 kHz)–(+75 kHz)] around the fourth electron gyroharmonic 4fc. The experiments were conducted at the HAARP facility in June 2014. A multi-frequency Doppler sounder (MDS), which measures the phase and amplitude of reflected sounding radio waves, complemented by the observations of the stimulated electromagnetic emission (SEE) were used for the diagnostics of the plasma perturbations. We detected noticeable plasma expulsion from the reflection region of the pumping wave and from the upper hybrid region, where the expulsion from the latter was strongly suppressed for f0 ≈ 4fc. The plasma expulsion from the upper hybrid region was accompanied by the sounding wave’s anomalous absorption (AA) slower development for f0 ≈ 4fc. Furthermore, slower development and weaker expulsion were detected for the height region between the pump wave reflection and upper hybrid altitudes. The combined MDS and SEE allowed for establishing an interconnection between different manifestations of the HF-induced ionospheric turbulence and determining the altitude of the most effective pump wave energy input to ionospheric plasma by using the dependence on the offset between f0 and 4fc.

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Vertical Motions in the Lower Ionosphere and Dynamics of the Ionospheric Plasma

2019 Russian Open Conference on Radio Wave Propagation (RWP) ◽

10.1109/rwp.2019.8810386 ◽

2019 ◽

Author(s):

Natalia Bakhmet'eva ◽

Valery Vyakhirev ◽

Elena Kalinina ◽

Ilya Zhemyakov ◽

Grigory Vinogradov

Keyword(s):

Ionospheric Plasma ◽

Lower Ionosphere

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Perspective Ground-based Method for Diagnostics of the Lower Ionosphere and the Neutral Atmosphere

Open Astronomy ◽

10.1515/astro-2017-0143 ◽

2013 ◽

Vol 22 (1) ◽

Author(s):

N. V. Bakhmetieva ◽

G. I. Grigoriev ◽

A. V. Tolmacheva

Keyword(s):

Radio Wave ◽

High Power ◽

Relative Concentration ◽

Spectral Characteristics ◽

Lower Ionosphere ◽

Internal Gravity Waves ◽

Spatial Period ◽

Neutral Atmosphere ◽

Radio Waves ◽

D Region

AbstractWe present a new perspective ground-based method for diagnostics of the ionosphere and atmosphere parameters. The method uses one of the numerous physical phenomena observed in the ionosphere illuminated by high-power radio waves. It is a generation of the artificial periodic irregularities (APIs) in the ionospheric plasma. The APIs were found while studying the effects of ionospheric high-power HF modification. It was established that the APIs are formed by a standing wave that occurs due to interference between the upwardly radiated radio wave and its reflection off the ionosphere. The API studies are based upon observation of the Bragg backscatter of the pulsed probe radio wave from the artificial periodic structure. Bragg backscatter occurs if the spatial period of the irregularities is equal to half a wavelength of the probe signal. The API techniques makes it possible to obtain the following information: the profiles of electron density from the lower D-region up to the maximum of the F-layer; the irregular structure of the ionosphere including split of the regular E-layer, the sporadic layers; the vertical velocities in the D- and E-regions of the ionosphere; the turbulent velocities, turbulent diffusion coefficients and the turbopause altitude; the neutral temperatures and densities at the E-region altitudes; the parameters of the internal gravity waves and their spectral characteristics; the relative concentration of negative oxygen ions in the D-region. Some new results obtained by the API technique are discussed.

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