共查询到20条相似文献,搜索用时 437 毫秒
1.
V. L. Frolov G. P. Komrakov V. E. Kunitsyn A. M. Padokhin A. E. Vasiliev G. A. Kurbatov 《Radiophysics and Quantum Electronics》2010,53(7):379-400
We present the results of experimental studies of the properties of the plasma-density disturbances created during heating
of the ionospheric F2 region by high-power HF radio waves radiated by the “Sura” heating facility (Radiophysical Research Institute, Nizhny Novgorod).
These experiments are specific in that they were performed in a sunlit (daytime) ionosphere when the generation of ionospheric
turbulence has specific features and the turbulence intensity level is low enough. The plasma-density disturbances induced
by high-power HF radio emission were sounded by signals of the GPS satellites, the line of sight to which crossed different
parts of the disturbed ionosphere region. Threshold powers of the excitation of artificial plasma-density variations as well
as spatial, temporal, spectral, and energy characteristics of the generated disturbances are determined. 相似文献
2.
V. P. Burmaka I. F. Domnin V. P. Uryadov L. F. Chernogor 《Radiophysics and Quantum Electronics》2009,52(11):774-795
We describe the results of using the incoherent scatter technique to observe time-altitude variations in regular parameters
of the ionospheric plasma and wave disturbances, which accompanied periodic modification of the near-Earth plasma by radio
waves emitted by the “Sura” facility. A distinctive feature of the experiments was that the processes in the ionosphere were
diagnosed at a distance of about 1000 km from the facility. It was found that the spectrum composition of wave disturbances
in the electron density was changing noticeably during the active experiment. Quasi-periodic processes in the ionosphere were
observed with a delay of about 40–60 min. The relative amplitude of wave disturbances was equal to 0.02–0.10, and the periods
were equal to 30, 60, 120, and 150–180 min. The observed effect can be explained by the generation and/or amplification of
traveling ionospheric disturbances. The results of theoretical estimations agree well with the observational data. 相似文献
3.
V. L. Frolov D. I. Nedzvetsky V. P. Uryadov V. A. Ivanov D. V. Ivanov A. R. Lashchevsky N. V. Ryabova 《Radiophysics and Quantum Electronics》2008,51(5):331-338
We present the results of studying the properties of artificial F-spread that appears on ionograms during heating of the ionospheric
F2 region by a high-power O-mode radio wave. It is shown that the regions of resonant interaction of a high-power radio wave
with plasma, where the pump-wave energy is almost totally absorbed and the plasma is subject to intense heating, affect significantly
the development of a self-focusing instability of a high-power radio wave and the generation of middle-scale (with characteristic
scales across the magnetic field l⊥ ≈ 0.4–1.5 km) artifical ionospheric inhomogeneities. It is established that the intensity of such inhomogeneities depends
on the sign and magnitude of detuning of the pump-wave frequency with respect to the electron gyroresonance harmonic frequency
Δf = fPW − nfce and has the minimum value for Δf ≈ −20 kHz, thus demonstrating the asymmetry of the gyroharmonic properties of their excitation
mechanism. Relationship between the observed phenomena and known characteristics of the artificial ionospheric turbulence
for fPW ≈ nfce is analyzed.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 51, No. 5, pp. 367–375, May 2008. 相似文献
4.
I. V. Despirak A. A. Lubchich V. Yu. Trakhtengerts 《Radiophysics and Quantum Electronics》2008,51(5):339-351
We analyze conditions for excitation of ULF waves in the ionospheric Alfvén resonator (IAR), taking into account the altitude-inhomogeneous
profile of the magnetospheric convection velocity. This profile is formed as a result of interaction of the convective flow
with the neutral atmosphere at altitudes 90–150 km. ULF waves comprise oblique Alfvén waves, trapped into the IAR, and ionospheric
drift waves, which are in resonance with them. These waves together form strongly anisotropic, closed current loops, whose
scale along the magnetic field greatly exceeds their transverse scale, i.e., lz ≫ l⊥, and can be considered Alfvén vortices. Within the framework of the proposed model of the ionosphere, we study the instability
threshold and the amplitude growth rate of the Alfvén vortices as functions of different parameters (wave vector k22A5, angle between the wave vector and the convection velocity, ratio of the Alfvén-wave and Pedersen conductivities, etc.).
Some estimates are given in application to the observed small-scale field-aligned currents in the auroral ionosphere.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 51, No. 5, pp. 376–390, May 2008. 相似文献
5.
L. M. Erukhimov A. A. Ponyatov V. P. Uryadov V. A. Ivanov V. V. Shumaev I. B. Egorov Yu. N. Cherkashin 《Radiophysics and Quantum Electronics》1996,41(1):1-6
The results of experimental studies of the fine structure of a signal in the vicinity of the maximum observed frequency (MOF)
on the Khabarovsk—Nizhny Novgorod path of oblique chirp sounding (OCS) are presented. Additional tracks were observed in the
region between the high-angle and low-angle rays during magneto-ionospheric disturbances. Under strong disturbances the ionograms
were of a spreading type in the vicinity of the MOF. The observed effect was modelled in the presence of travelling ionospheric
disturbances (TID) with different parameters. It is shown that the stratification of the high-angle ray into several additional
tracks is a maximum for TID with vertical scales
km whose wave fronts make angles about 0–10° with the horizontal line. The possibilities of using the Pedersen mode as a
probing wave for diagnostics of the fine structure of the ionosphere in the vicinity of the F-layer maximum are discussed.
Radiophysical Research Institute, Nizhny Novgorod; State Technical University of Ioshkar-Ola, Mari Republic; Institute of
Terrestrial Magnetism, Ionosphere, and Radio Wave Propagation, Russian Academy of Sciences, Troitsk, Moscow region, Russia.
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 41, No. 1, pp. 3–12, January, 1998. 相似文献
6.
E. D. Tereshchenko R. Yu. Yurik T. K. Yeoman T. R. Robinson 《Radiophysics and Quantum Electronics》2008,51(11):858-861
We present the first results of observations of the stimulated electromagnetic emission (SEE) in the ionosphere modified by
the Space Plasma Exploration by Active Radar (SPEAR) heating facility. Observation of the SEE is the key method of ground-based
diagnostics of the ionospheric plasma disturbances due to high-power HF radiation. The presented results were obtained during
the heating campaign performed at the SPEAR facility in February–March 2007. Prominent SEE special features were observed
in periods in which the critical frequency of the F
2 layer was higher than the pump-wave frequency (4.45 MHz). As an example, such special features as the downshifted maximum
and the broad continuum in the region of negative detunings from the pump-wave frequency are presented. Observations clearly
demonstrate that the ionosphere was efficiently excited by the SPEAR heating facility despite the comparatively low pump-wave
power.
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 51, No. 11, pp. 951–955, November 2008. 相似文献
7.
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
8.
V. A. Alimov F. I. Vybornov E. N. Myasnikov A. V. Rakhlin 《Radiophysics and Quantum Electronics》2008,51(11):874-879
We show the results of the first experimental studies of the multifractal structure of the developed artificial ionospheric
turbulence. As a result of the special multifractal analysis of the recorded amplitudes of signals from the orbital satellites,
which were obtained during the experiments on radio tomography of the irregularities excited in the ionosphere by the powerful
mid-latitude heating facility “Sura,” it is found that the characteristic multifractal structure of these records is caused
by the nonuniform spatial distribution of the small-scale fluctuations of the electron number density in the artificial irregularities
of the ionospheric plasma. Comparative analysis is performed for the multifractal spectra of fluctuations of both the amplitudes
and energies of signals received from the orbital satellites upon radio transmission probing of the region of artificial ionospheric
turbulence by these signals at three observation points located near the “Sura” heating facility and spaced apart to a distance
of about 100–150 km.
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 51, No. 11, pp. 970–976, November 2008. 相似文献
9.
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
10.
A theoretical analysis of the vertical propagation of large-scale wave disturbances in the F region and outer ionosphere is
presented. The analysis has included all the major factors influencing the dynamics of the ionospheric plasma under mid-latitude
conditions. It is shown that the disturbances propagating downward in a strongly inhomogeneous medium rise in intensity up
to the heights of the F2-layer maximum and are damped then in the lower layers of the ionosphere. This mechanism can be considered a source responsible
for the inhomogeneous structure of the upper ionosphere.
State University, Irkutsk, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 41, No. 9, pp.
1086–1092, September, 1998. 相似文献
11.
N. A. Barkhatov O. M. Barkhatova G. I. Grigor’ev 《Radiophysics and Quantum Electronics》2012,55(6):382-390
We obtain dispersion relations for magnetogravity waves in the ionosphere with allowance for the combined influence of magnetic field, gravity, and finite conductivity within the framework of the hydrodynamic approximation. The required conditions are fulfilled in the ionosphere at altitudes over or about 250 km. The auroral electrojet is considered as a source of magnetogravity waves which are frequently observed as traveling ionospheric disturbances. The contribution of magnetogravity waves to the ionospheric disturbances is determined on the basis of analyzing the data from the vertical sounding of the ionospheric F2 layer and the geomagnetic disturbances along the chosen magnetic meridian and on its sides. The features of the obtained dynamic spectra of magnetogravity waves agree with the characteristic frequencies and velocities determined by the calculated dispersion curves. As a result, we confirm the fact that magnetogravity waves stipulate some traveling ionospheric disturbances and can be used for diagnostics of the ionospheric parameters. 相似文献
12.
We report on the results of studying the lower ionosphere by a method based on the resonant scattering of radio waves by artificial
periodic inhomogeneities of the ionospheric plasma. Different aspects of studying the sporadic E layer such as the influence of the vertical transfer on its formation, the possibility of examination of its ion composition,
and the influence of the ionosphere heating on the layer characteristics are discussed. The results of determining the parameters
of the E
s layer and some characteristics of the lower ionosphere during the creation of artificial periodic inhomogeneities at two
frequencies are presented.
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 51, No. 11, pp. 956–969, November 2008. 相似文献
13.
E. N. Sergeev S. M. Grach G. P. Komrakov V. L. Frolov P. Stubbe B. Thide T. Leyser T. Carozzi 《Radiophysics and Quantum Electronics》1999,42(8):715-727
We present the results of experimental studies of the evolution of diagnostic stimulated electromagnetic emission of the ionosphere
(DSEE) in a broad range of the pump and probing wave frequencies under sounding of the F-layer disturbed by powerful HF radio
waves. We study the parameters of the overshoot effect in SEE evolution during the relaxation stage of artificial small-scale
irregularities and show that the amplification of DSEE (inverse overshoot effect) is related to the relaxation of the anomalous
attenuation due to scattering at these irregularities. We have found that the characteristic time scales of development of
the overshoot effect decrease and its value increases as the pump wave frequency decreases from 6 to 4 MHz and as the probed
volume moves from the edge to the central part of the disturbed volume. We relate the effects observed to the increasing intensity
of the irregularities with scales l∼∼3−10 m.
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 42, No. 8, pp. 810–824, August 1999. 相似文献
14.
V. L. Frolov V. O. Papoport G. P. Komrakov A. S. Belov G. A. Markov M. Parrot J. L. Rauch E. V. Mishin 《Radiophysics and Quantum Electronics》2008,51(11):825-833
We report on the French DEMETER and American DMSP satellite measurements of largescale field-aligned plasma-density perturbations
(ducts) induced in the topside ionosphere by the ionospheric F
2-layer pumping by means of high-power HF radio waves from the “Sura” heating facility. Characteristics of such plasma perturbations
and conditions of their formation are determined.
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 51, No. 11, pp. 915–924, November 2008. 相似文献
15.
G. G. Vertogradov V. G. Vertogradov V. P. Uryadov 《Radiophysics and Quantum Electronics》2006,49(12):923-936
We present the results of experimental studies of ionospheric wave-like disturbances on the basis of oblique chirp sounding
data for the mid-latitude paths Cyprus-Rostov-on-Don and Inskip-Rostov-on-Don. Twenty-four-hour measurements were performed
in January-May and October–November, 2005 and in January, 2006. The spectral analysis of variations in the maximum observed
frequency (MOF) is performed. It is shown that the spectra of the MOF fluctuations have a well pronounced line structure.
The amplitude-dominant spectral harmonics are concentrated near the frequencies 0.18–0.8 mHz (20–90-min periods). We give
the results of modeling of radio waves propagation in the presence of traveling ionospheric disturbances and compare the calculated
and experimental data.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radio.zika, Vol. 49, No. 12, pp. 1015–1029, December 2006. 相似文献
16.
G.G. Vertogradov V.P. Uryadov V.G. Vertogradov 《Radiophysics and Quantum Electronics》2005,48(6):405-419
We present the results of experimental studies of the distance-frequency and amplitude-frequency characteristics of the ionospheric
HF channel on mid-latitude paths of oblique chirp sounding. It is shown that the maximum observed frequencies (MOFs) are subject
to short-period variations with the quasi-periods from 30 min to 2 h.The amplitude of the MOF variations reaches 2 MHz and
can increase up to 5–8 MHz on the Cyprus—Rostov-on-Don one-hop path in the sunrise-sunset time. It is established that the
MOF fluctuations are accompanied by pronounced “cusp” features occurring in the upper rays and moving with time to the region
of shorter delays, i.e., from lower to higher frequencies. The amplitude-frequency characteristics of individual propagation
modes undergo deep fluctuations (up to 20–30 dB)whose quasi-period and depth depend on the frequency. It is shown that the
appearance of fluctuations is caused by interference of the unresolved rays within the limits of one propagation mode. Based
on the modeling, it is shown that “cusps” in oblique-sounding ionograms are due to the influence of traveling ionospheric
disturbances (TIDs). The TID parameters are estimated. It is shown that conditions of the formation of “ cusps” in the distance-frequency
characteristics depend on the TID amplitude, the wavelength of the disturbance wave, and the direction of its phase front
with respect to the propagation path. The effect of quasi-regular frequency modulation of the Pedersen mode with a period
of 250–300 kHz on the Cyprus-Rostov-on-Don chirp-sounding path is found. Altitude stratification of the ionosphere near the
F-layer maximum, which is responsible for the focusing and defocusing of the Pedersen mode, is estimated. It is established
that the stratification scale amounts to approximately 200–250 m.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 48, No. 6, pp.455–471, June 2005. 相似文献
17.
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
18.
V. A. Alimov F. I. Vybornov L. M. Erukhimov G. P. Komrakov N. A. Mityakov A. V. Rakhlin 《Radiophysics and Quantum Electronics》1997,40(6):456-458
We show some results of experiments on synchronous sounding of the ionosphere by short-wave signals at the Radiophysical Research
Institute’s test site in Zimenki and Vasil’sursk, Nizhniy Novgorod province, during ionospheric modification by high-power
short radiowaves from transmitters of the “Sura” facility in Vasil’sursk. In the course of experiments we proved directly
the decisive role of large-scale inhomogeneities of the ionospheric plasma with dimensions of from several kilometers to several
dozens of kilometers in the formation of artificial F- spread. The small-scale inhomogeneities with dimensions smaller than
1 km, which are localized in a relatively thin layer near the reflection level of a high-power short radiowave, emerged only
at sounding waves, propagating (reflected) in the immediate vicinity of the center of the heating region.
Radiophysical Research Institute, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika,
Vol. 40, No. 6, pp. 688–692, June, 1997. 相似文献
19.
G. N. Boiko S. M. Grach E. N. Sergeev G. P. Komrakov N. A. Mityakov K. Groves 《Radiophysics and Quantum Electronics》1999,42(7):601-608
On October 24, 1997, from 16:00 to 19:30 LT, during experiments on the artificial mofification of ionosphere by powerful HF
radiation using spaced heating, we recorded twice a significant (tens of percent) decrease of the electron number density
in the F-layer, synchronous with the operation of the heating trnasmitters. The critical frequency of this layer decreased
by 10–20%. This points to the possibility of artificial generation of large-scale inhomogeneities of the ionospheric plasma
density using spatially split heating.
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 42, No. 7, pp. 682–690, January 1999. 相似文献
20.
Some distinctive features in the behavior of small-scale artificial ionospheric irregularities at mid-and high latitudes 总被引:1,自引:0,他引:1
N. F. Blagoveshchenskaya T. D. Borisova V. A. Kornienko V. L. Frolov M. T. Rietveld A. Brekke 《Radiophysics and Quantum Electronics》2007,50(8):619-632
We present the results of experimental studies of some features in the behavior of small-scale artificial irregularities (SSAIs)
at mid-and high latitudes based on the “Sura” and EISCAT/HEATING HF facilities. Observations were performed by the method
of aspect scattering using a network of diagnostic paths having a common reception point located near St. Petersburg. We found
that an extremely long duration of the second (slow) stage of SSAI relaxation of up to 5 min occurs in the evening hours when
the ionosphere above the “Sura” facility is illuminated by the Sun, but the solar terminator travels through the magnetically
conjugated ionosphere. The conjecture is made that the processes initiated by the terminator are mostly responsible for secondary
ionospheric turbulence maintaining the irregularities above “Sura.” A drastic increase in the Doppler spectra width of the
scattered signals is revealed when the magnetically conjugate point of the ionosphere is located on the shade side of the
terminator, but the ionosphere above the “Sura” facility is still lighted. It is assumed that the “ run away” of photoelectrons
from the day to the night side could reduce the threshold of excitation of artificial irregularities, leading to an increase
in their intensity. The presence of fairly intense scattered signals was detected from the “Sura” and EISCAT/HEATING experimental
results both under conditions of pulsed HF heating after continuous heater-on periods and cycled HF heating by short pulses.
In the case of pulsed heating by short pulses with duration τp < 100 ms and average radiated power Pa below the threshold power Pthr of the SSAI generation cutoff the irregularities can be maintained due only to striction parametric instabilities. The excitation
of irregularites under the cycled HF pumping with the pulse duration τp = 384 ms for Pa comparable with Pthr was detected. The aspect-angle dependence, or the so-called magnetic zenith effect, was found in the SSAI intensity. The
residual turbulence aftereffects played a significant role in the SSAI development.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 50, No. 8, pp. 678–694, August 2007. 相似文献