Ionospheric wave processes during HF heating experiments

Blagoveshchenskaya, N. F.; Andreev, Andrey D.; Kornienko, V. N.

doi:10.1016/0273-1177(95)00010-c

Cited by 8 publications

(5 citation statements)

References 4 publications

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“…Oblique‐incidence sounding has been employed for studying dynamic processes successfully and for a sufficiently long time (Blagoveshchenskaya et al, ; Chernogor et al, ; Garmash et al, ; Garmash et al, ). To continuously monitor dynamic processes occurring in the ionosphere, specialists from V. N. Karazin Kharkiv National University, Ukraine, and the Harbin Engineering University, the PRC, have developed the multifrequency multipath radio system in the 10‐kHz to 30‐MHz band and placed it in operation in 2018.…”

Section: Introductionmentioning

confidence: 99%

Radio Monitoring of Dynamic Processes in the Ionosphere Over China During the Partial Solar Eclipse of 11 August 2018

et al. 2020

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We briefly describe the multifrequency multiple‐path radio system and illustrate its observational capabilities by performing, as an example, the study of dynamic processes that occurred in the ionosphere over China during the partial solar eclipse on August 11 2018. This system, based on the software‐defined radio technology and capable of operating in the 10‐kHz to 30‐MHz band, has been developed jointly by Harbin Engineering University, the People's Republic of China, where it is located, and V. N. Karazin National University, Ukraine. The principle of the system operation is based on measurements of a Doppler shift of frequency. The implementation of Marple's algorithm for autoregression spectrum analysis has permitted an increase in a Doppler resolution down to 0.02 Hz and in a temporal resolution down to 7.5 s. The number of radio propagation paths and their orientation depend on the specifics of problems being solved. The interpretation of the eclipse effects is complicated by processes launched by the dusk terminator. The eclipse was associated with an increase in the number of rays, the generation of oscillation processes in the atmospheric gravity wave range of periods, and with a negative Doppler shift of frequency at first and a positive shift of smaller magnitude subsequently. The solar eclipse launched ~9–14% amplitude quasiperiodic oscillations in the electron density, while a maximum decrease of order 26% was observed over the Hailar–Harbin path in the ionospheric E region. The latter value does not virtually differ from theoretical estimates.

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Section: Introductionmentioning

confidence: 99%

Radio Monitoring of Dynamic Processes in the Ionosphere Over China During the Partial Solar Eclipse of 11 August 2018

et al. 2020

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“…Large-scale (kilometer size) irregularities are best interpreted in terms of thermally driven self-focusing of the incident HF electromagnetic wave [Duncan and Sheerin 1985]. Small-scale (meter size) field-aligned striations are generally explained as differential plasma heating from enhanced Langmuir wave collisional dissipation or HF scatter from the induced plasma oscillations [Blagoveshchenskaya et al 1995]. Concerning the nature and origin of Langmuir wave, a popular view is the theory of thermal parametric (resonant) instability developed at the upper hybrid resonance altitude [Das and Fejer 1979].…”

Section: Introductionmentioning

confidence: 99%

Influences of the state of ionospheric background on ionospheric heating effects

Hao

Li²,

Che³

et al. 2014

Annals of Geophysics

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According to the well-performed ionospheric heating experiments at Arecibo in the low latitudes as well as at Tromsø in the high latitudes, the large-scale modification effects are simulated under an assumption of equivalent conditions, i.e., with the same effective radiative power and the same ratio of the heating frequency fHF to the critical frequency of ionospheric F region foF2. The findings are extensively exploited to verify the validation of our model by comparison to the experimental results. Further, a detailed study is carried out on the influences of the background electron density gradient as well as the ratio of fHF to foF2 on heating effects. Conclusions are drawn as follows: under certain conditions, a smaller electron density gradient of background ionospheric F region leads to a better ionospheric heating effect; during over-dense heating, the heating effects are enhanced if the ratio of fHF to foF2 increases, which is slightly limited by the resultant elevation of the reflection height. However, there might be a better ratio range with small values of the ratio of fHF to foF2, e.g., [0.5, 0.7] in the current study. Finally, we analyzed how to select heating parameters efficiently under adverse conditions so to obtain relatively effective results.

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“…Gurevich et al (1976) and Golov and Kochubei (1988) have studied the self-focusing of an electromagnetic beam in the ionosphere, using rather simple models. Blagoveshchenskaya et al (1995) invoked ponderomotive nonlinearity as the self-focusing mechanism. However, Gurevich (1978) has pointed out that the ponderomotive nonlinearity in the ionosphere is two to three orders of magnitude weaker than the collisional one.…”

Section: Introductionmentioning

confidence: 99%

Self-focusing of electromagnetic beams in the ionosphere considering Earth's magnetic field

Sodha¹,

Sharma

2008

J. Plasma Phys.

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In this paper the focusing/defocusing of (i) a single Gaussian electromagnetic beam and (ii) a number of coaxial Gaussian electromagnetic beams, propagating in the extraordinary mode along the Earth's magnetic field in the ionosphere has been investigated in the paraxial approximation. The growth of a sinusoidal instability on account of self-focusing has also been studied. The nonlinearity in the dielectric function, responsible for the focusing/defocusing arises from the redistribution of the electron density, caused by the non-uniform distribution of the electron temperature. The electron temperature is determined by the energy balance for electrons/ions taking into account the Ohmic heating, the collisions and the radiation from the sun. The wave frequency has been assumed to be greater than the plasma frequency. The electron cyclotron frequency due to the Earth's magnetic field in the ionosphere is much larger than the electron collision frequency. This is specifically true for a height of 150 km. Numerical results have been presented for a range of parameters and a discussion of the same has been presented.

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Ionospheric wave processes during HF heating experiments

Cited by 8 publications

References 4 publications

Radio Monitoring of Dynamic Processes in the Ionosphere Over China During the Partial Solar Eclipse of 11 August 2018

Radio Monitoring of Dynamic Processes in the Ionosphere Over China During the Partial Solar Eclipse of 11 August 2018

Influences of the state of ionospheric background on ionospheric heating effects

Self-focusing of electromagnetic beams in the ionosphere considering Earth's magnetic field

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