共查询到20条相似文献,搜索用时 484 毫秒
1.
N. V. Bakhmet'eva V. V. Belikovich L. M. Kagan A. A. Ponyatov A. V. Tolmacheva M. C. Kelley M. J. Nicolls 《Radiophysics and Quantum Electronics》2005,48(9):673-685
We present the results of studying the lower ionosphere in 2000–2004 at the “Sura” heating facility by the method of resonance
scattering of radio waves from artificial periodic inhomogeneities of the ionospheric plasma. Experimental data on a study
of the sunset–sunrise phenomena in the ionospheric D region and the possibility of determining the concentrations of atomic
oxygen and excited molecular oxygen are discussed. The results of studying the sporadic layers of ionization are presented
and the method for a study of ion composition of the Es layer is discussed. Data of the August 2004 experiments on a study of the influence of heating the ionosphere on the Es layer and characteristics of artificial periodic inhomogeneities are presented. Prospects for further research are discussed.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 48, No. 9, pp. 757–771, September 2005. 相似文献
2.
N. V. Bakhmet’eva V. V. Belikovich M. N. Egereva A. V. Tolmacheva 《Radiophysics and Quantum Electronics》2010,53(2):69-81
We present new results of studying the artificial periodic irregularities produced in the ionosphere by the radio emission
of the high-power heating facility “Sura” during the period of observations of the sporadic E layer. Basing on the measurement results for the velocity of the vertical plasma motion and the electron profile density
in the E region of the ionosphere, which were obtained by the method of resonance scattering of radiowaves by an artificially produced
periodic structure, we analyze the possibility to produce a sporadic E layer by driving metal ions affected by the vertical shear of the velocity, which occurs at these altitudes due to the propagation
of internal gravity waves. The parameters of these waves are evaluated, as well as the mass and concentration of metal ions
in the sporadic E layer. 相似文献
3.
We present the results of new studies of the sporadic E layer in the case of heating of the ionosphere by high-power HF radio
emission. The measurements were performed at the “Sura” heating facility. Ionosphere was modified by high-power radio emission
from the “Sura” facility and was sounded by the probing radio waves of the same frequency and mode. The heating of the ionosphere
resulted in the formation of artificial periodic inhomogeneities, and an increase in the intensity of all signals scattered
by the D, E, and F regions and the sporadic E layer by 5–20 dB was observed. The increase was observed during heating of the
ionosphere by each magnetoionic component, but was smaller for heating by an ordinary-mode wave. This effect was resonant
and disappeared as a result of the frequency detuning down to 85 kHz. During the ionospheric modification, the signal-intensity
increased due to modulation of the natural profile of the electron number density by the artificial periodic structure.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 50, No. 8, pp. 695–708, August 2007. 相似文献
4.
V. V. Belikovich N. V. Bakhmet’eva V. N. Bubukina V. D. Vyakhirev E. E. Kalinina G. P. Komrakov A. V. Tolmacheva 《Radiophysics and Quantum Electronics》2008,51(6):431-437
We present the first results of determining the electron number density in the ionospheric E region by a novel technique based on the creation of artificial periodic irregularities when the ionosphere is affected by
powerful radio emission at two frequencies. Using the results of the measurements performed in October 2006 during heating
of the ionosphere by the “Sura” facility radiation at frequencies 4.7 and 5.6 MHz, we obtained the electron number density
profiles in an altitude range of 100 to 110 km. Features of the procedure of measurement and calculation of the electron number
density are described in detail. It is shown that the method can be used for a study of the irregular structure of the lower
ionosphere.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 51, No. 6, pp. 477–484, June 2008. 相似文献
5.
N. V. Bakhmet’eva G. I. Grigoriev A. V. Tolmacheva E. E. Kalinina 《Russian Journal of Physical Chemistry B, Focus on Physics》2018,12(3):510-521
A method for studying the Earth’s ionosphere at altitudes of the mesosphere and lower thermosphere based on creating artificial periodic irregularities in the ionospheric plasma by means of powerful radio waves is breafly described. Methods for determining the temperature and density of the neutral component and the velocity of vertical and turbulent motions by measuring the characteristics of the signal backscattered by the irregularities are described. The results of experiments performed on a SURA heating facility aimed at a comprehensive investigation of the natural processes occurring in the Earth’s lower ionosphere due to the propagation of atmospheric waves and turbulent phenomena are examined. Based on measurements of the amplitude and phase of the signal scattered by periodic irregularities, the most important characteristics of the neutral and plasma components of the Earth’s atmosphere at altitudes of the mesosphere and lower thermosphere are determined. Further research on the subject is discussed. 相似文献
6.
V. A. Alimov F. I.Vybornov E. N. Myasnikov A. V. Rakhlin V. L. Frolov 《Radiophysics and Quantum Electronics》2009,52(9):609-617
We present the results of the experiment on studying the multifractal structure (with inhomogeneity sizes from tens to hundreds
of meters across the Earth’s magnetic field) of the artificial ionospheric turbulence when the midlatitude ionosphere is affected
by high-power HF radio waves. The experimental studies were performed on the basis of the “Sura” heating facility with the
help of radio sounding of the disturbed region of the ionospheric plasma by signals from the Earth’s orbital satellites. The
influence of the magnetic zenith effect on measured multifractal characteristics of the small-scale artificial turbulence
of the midlatitude ionosphere was examined. In the case of vertical radio sounding of the disturbed ionosphere region, the
measured multipower and generalized multifractal spectra of turbulence coincide well with similar multifractal characteristics
of the ionospheric turbulence under natural conditions. This result is explained by the fact that the scattering of signals
by weak quasi-isotropic small-scale inhomogeneities of the electron number density in a thick layer with a typical size of
several hundred kilometers above the region of reflection of high-power HF radio waves gives the major contribution to the
observed amplitude fluctuations of received signals. In the case of oblique sounding of the disturbance region at small angles
between the line of sight to the satellite and the direction of the Earth’s magnetic field, the nonuniform structure of the
small-scale turbulence with a relatively narrow multipower spectrum and small variations in the generalized multifractal spectrum
of the electron number density was detected. Such a fairly well ordered structure of the turbulence is explained by the influence
of the magnetic zenith effect on the generation of anisotropic small-scale artificial turbulence in a thin layer having a
typical size of several ten kilometers and located below the pump-wave reflection height in the upper ionosphere. 相似文献
7.
Frolov V. L. Kagan L. M. Komrakov G. P. Sergeev E. N. Shorokhova E. A. 《Radiophysics and Quantum Electronics》2002,45(12):917-928
We present the results of experiments on modification of the sporadic E-layer of the Earth's ionosphere by a powerful vertical beam of HF radio waves. The experiments were performed at the Sura heating facility (Radiophysical Research Institute, Nizhny Novgorod) from May 31 to June 4, 2001. The main results were obtained in May 31 from 17:30 to 20:00 MSK, when the Es layer was fairly stable and the pump frequency was in the range where this layer was transparent. The diagnostics of the ionosphere was performed using X-mode probe waves in the frequency range fpr=4.3-7.8 MHz. The ionosphere plasma heating was accompanied by an increase in the intensity of probe waves, reflected from the Es layer, with frequencies close to or slightly higher than the critical frequency of the layer. Artificial fluctuations of the reflected signal appeared in the entire frequency range of sounding. We consider the dynamical characteristics of the observed phenomena and their dependence on the frequency fpr and the parameters of the Es layer. 相似文献
8.
N. F. Blagoveshchenskaya T. D. Borisova V. A. Kornienko A. S. Janzhura A. S. Kalishin T. R. Robinson T. K. Yeoman D. M. Wright L. J. Baddeley 《Radiophysics and Quantum Electronics》2008,51(11):847-857
We present the results of experimental studies of specific features in the behavior of small-scale artificial field-aligned
irregularities (AFAIs) and the DM component in the spectra of stimulated electromagnetic emission (SEE). Analysis of experimental
data shows that AFAIs in the polar ionosphere are generated under different background geophysical conditions (season, local
time, the presence of sporadic layers in the E region, etc.). It is shown that AFAIs can be excited not only in the F region, but also in “thick” sporadic E
s layers of the polar ionosphere. The AFAIs were observed in some cycles of heating when the HF heater frequency exceeded the
critical frequency by 0.3–0.5 MHz. Propagation paths of diagnostic HF radio waves scattered by AFAIs were modelled for geophysical
conditions prevailing during the SPEAR heating experiments. Two components, namely, a narrow-banded one with a Doppler-spectrum
width of up to 2 Hz and a broadband one observed in a band of up to 20 Hz, were found in the sporadic E
s layer during the AFAI excitation. Analysis of the SEE spectra shows that the behavior of the DM component in time is irregular,
which is possibly due to strong variations in the critical frequency of the F
2 layer from 3.5 to 4.6 MHz. An interesting feature observed in the SPEAR heating experiments is that the generation of the
DM component was similar to the excitation of AFAIs when the heater frequency was up to 0.5 MHz higher than the critical frequency.
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 51, No. 11, pp. 939–950, November 2008. 相似文献
9.
Tuning of the open‐circuit voltage by wide band‐gap absorber and doped layers in thin film silicon solar cells
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Shuo Wang Vladimir Smirnov Tao Chen Xiaodan Zhang Shaozhen Xiong Ying Zhao Friedhelm Finger 《固体物理学:研究快报》2015,9(8):453-456
We present an experimental study combined with computer simulations on the effects of wide band‐gap absorber and window layers on the open‐circuit voltage (Voc) in single junction thin film silicon solar cells. The quantity ΔEp, taking as the difference between the band gap and the activation energy in ?p? layer, is treated as a measure of the p‐layer properties and shows a linear relation with Voc over a range of 100 mV with a positive slope of around 430 mV/eV. Two limiting mechanisms of Voc are identified: the built‐in potential at lower ΔEp and the band gap of the absorber layer at higher ΔEp. The results of the experimental findings are confirmed by computer simulations. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献
10.
Bakhmet'eva N. V. Belikovich V. V. Benediktov E. A. 《Radiophysics and Quantum Electronics》2001,44(12):924-934
We present new results of our studies of the irregular structure of the ionosphere using artificial periodic inhomogeneities (APIs) of the ionospheric plasma. The observations were carried out from 9:00 to 17:00 in August 10–12, 1999 with a height step of 0.7 km and digital registration and real-time processing of the signal quadratures. It is shown that in many cases, the amplitude of the scattered signal is determined by the interference of radio waves scattered on APIs and on natural ionospheric formations including sporadic layers and large-scale natural irregularities. This allows one to study the irregular structure of the lower ionosphere by analyzing height-time dependences of the amplitude and phase of the scattered signal. 相似文献
11.
N. V. Bakhmet’eva V. V. Belikovich Yu. A. Ignat’ev A. A. Ponyatov 《Radiophysics and Quantum Electronics》1999,42(1):22-30
We propose a calculation technique for the main characteristics of a sporadic E-layer, including the effective recombination
coefficient, the relative content of meteor and atmospheric ions in the layer, and the time of its evolution. This technique
is based on measurements of vertical plasma velocities by the method of resonance scattering of radio waves by artificial
periodic inhomogeneities of the electron density. The contribution of internal gravity waves and turbulent motions to the
formation of sporadic layers is estimated. The characteristic values of the turbulent velocity measured by this method at
the heights of the turbopause are presented. The possible mechanisms of mid-latitude sporadic E-layer formation at heights
of 90 to 120 km are considered. Experimental studies confirmed the main statements of the wind shear theory concerning the
determining role of the redistribution of ionization under the action of atmospheric winds with vertical gradient of velocity
in the formation of Es.
Deceased.
Radiophysical Research Institute, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika,
Vol. 42, No. 1, pp. 26–35, January, 1999. 相似文献
12.
V. V. Belikovich N. V. Bakhmeteva E. E. Kalinina A. V. Tolmacheva 《Radiophysics and Quantum Electronics》2006,49(9):669-674
We propose a new method for determination of the electron number density in the E region of the ionosphere on the basis of
scattering of radio waves from artificial periodic inhomogeneities formed by the high-power radio emission at two frequencies
and having different spatial periods. The ratio of relaxation times of the artificial periodic inhomogeneities at a given
altitude is determined only by the ratio of their spatial periods, which makes it possible to determine electron number density.
The paper presents the corresponding calculations and the estimates of possible measurement errors.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 49, No. 9, pp. 744–750, September 2006. 相似文献
13.
Quality theoretical analysis allows us to assume that artificial plasma inhomogeneities in the ionosphere modified by high-power decametric radiowaves could be space modes of thermogravitational convection. Effects observed in the scattering of test 10-m radiowaves are interpreted as anindication of thermogravitational convection in heated ionospheric plasma.Translated from Izvestiya Vyssikh Uchebnykh Zavedenii, Radiofizika, Vol. 39, No. 5, pp. 568–578, May, 1996. 相似文献
14.
E. A. Benediktov V. V. Belikovich N. V. Bakhmet'eva A. V. Tolmacheva 《Radiophysics and Quantum Electronics》2002,45(5):343-357
This paper is dedicated to a new method of ionospheric studies, developed at the Radiophysical Research Institute (NIRFI) and based on the creation of artificial periodic inhomogeneities (APIs) of the ionospheric plasma. We review the techniques and present the results of determination of the basic parameters of the ionosphere and atmosphere. 相似文献
15.
V. L. Frolov G. G. Vertogradov V. G. Vertogradov 《Radiophysics and Quantum Electronics》2008,51(4):247-258
We analyze variations in characteristics of the diagnostic stimulated electromagnetic emission of the ionosphere in the evening
hours including the times of sunset both on the Earth’s surface at the observation point and in the ionosphere over it. It
is found that an increase in typical times of evolution of the diagnostic emission begins to be recorded just before the sunset
on the Earth’s surface when the ionosphere is illuminated and its parameters are not significantly changed yet. We state that
the typical times of evolution of the diagnostic emission increase when the pump-wave frequency approaches the critical frequency
of the ionospheric F2 layer, but such an effect is not as significant as when passing from the illuminated to the unilluminated ionosphere. It
is established that at the stage of diagnostic sounding the pump-wave pulse power does not exert any notable influence on
the first (fast) stage of relaxation of small-scale artificial ionospheric irregularities, but can increase the decay time
of the irregularities at the second (slow) stage of relaxation. Capabilities of the method for a study of artificial plasma
turbulence using the diagnostic stimulated electromagnetic emission are discussed.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 51, No. 4, pp. 273–286, April 2008. 相似文献
16.
V. V. Belikovich N. V. Bakhmet’eva V. N. Bubukina A. A. Karashtin A. V. Tolmacheva 《Radiophysics and Quantum Electronics》1998,41(9):727-731
We report on the studies of the lower ionosphere with improved height resolution using artificial periodic irregularities.
This method is useful for studying the irregular structure of the ionosphere.
Radiophysical Research Institute, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika,
Vol. 41, No. 9, pp. 1077–1085, September, 1998. 相似文献
17.
This paper proposes a new n +-charge island (NCI) P-channel lateral double diffused metal-oxide semiconductor (LDMOS) based on silicon epitaxial separation by implantation oxygen (E-SIMOX) substrate.Higher concentration self-adapted holes resulting from a vertical electric field are located in the spacing of two neighbouring n +-regions on the interface of a buried oxide layer,and therefore the electric field of a dielectric buried layer (E I) is enhanced by these holes effectively,leading to an improved breakdown voltage (BV).The V B and E I of the NCI P-channel LDMOS increase to-188 V and 502.3 V/μm from 75 V and 82.2 V/μm of the conventional P-channel LDMOS with the same thicknesses SOI layer and the buried oxide layer,respectively.The influences of structure parameters on the proposed device characteristics are investigated by simulation.Moreover,compared with the conventional device,the proposed device exhibits low special on-resistance. 相似文献
18.
E. A. Benediktov N. P. Goncharov Yu. A. Ignat'ev S. N. Matyugin P. B. Shavin 《Radiophysics and Quantum Electronics》1984,27(1):8-12
Experimental results are given on an investigation of the parameters of an artificial region of disturbance (RD) of the ionosphere arising under the action on the ionosphere of strong SW radio emission (Peq 20 MW) with a frequency of 5.75 MHz. It is shown that in this case an RD is formed in the F layer of the ionosphere with Ne/Ne 5 · 10–2 and nonuniformities of Ne are generated or amplified. Such an RD acts as a focusing lens on probe radio waves passing through it. In the E layer of the ionosphere Ne increases by 5 · 10–2 in about 30 sec.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 27, No. 1, pp. 12–17, January, 1984. 相似文献
19.
We employ artificial neural networks (ANNs) to develop an algorithm yielding 1-, 2-, 3-, 12-, and 24-hour forecasts of the critical frequency of the ionospheric F2 layer. A search for suitable training set and ANN architecture is performed. The use of auxiliary input data, such as the solar-wind and interplanetary magnetic-field parameters, as well as the geomagnetic-activity indices, makes it possible not only to improve the prediction efficiency but also to find some regularities in the critical-frequency behavior. The results of this work can be applied to the prompt correction of the ionosphere model, aimed at improving the ionospheric HF radio communication.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 48, No. 1, pp. 1–15, January 2005. 相似文献
20.
O. M. Barkhatova A. S. Smirnova R. I. Ulybina 《Radiophysics and Quantum Electronics》2009,52(2):100-107
The cause-and-effect relation between variations in the critical frequency of the F
2 subauroral ionospheric layer and the key solar-magnetospheric parameters is studied. The features of the dependence of the
critical frequency of the subauroral ionosphere on the value and components of the interplanetary magnetic field, the solar-wind
parameters, the X-ray and ultraviolet radiation intensities, the solar zenith angle, and the intensity of precipitation of
low-energy particles are established. Within the framework of this study, codes allowing one to solve the problems of predicting
the critical frequency of the ionosphere by the method of artificial neural networks has been developed. The neural-network
forecasting experiments reveal the characteristic times of the ionospheric response to magnetospheric disturbancs. The found
optimal architecture of the neural network allows us to predict the time series of the critical frequency of the high-latitude
ionosphere for the interval 0.5–3 h with an accuracy of up to 93%. The obtained linear and nonlinear dependences of the critical
frequency of the ionospheric F
2 layer on the geophysical parameters can be used for developing ionospheric models required for determining the maximum usable
frequency of HF radio communication.
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 52, No. 2, pp. 109–117, February 2009. 相似文献