共查询到20条相似文献,搜索用时 15 毫秒
1.
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
2.
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
3.
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
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.
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
6.
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
7.
V. A. Liperovsky C. V. Meister S. A. Senchenkov K. V. Popov M. A. Oleynik E. V. Liperovskaya 《Radiophysics and Quantum Electronics》1996,39(2):166-172
The paper is devoted to questions connected with the possible effects of excitation of local current systems in the E-region of the ionosphere on the basis of a quasi-three-dimensional model. A hypothesis of local current generation caused by the action of short-time intense neutral winds on sporadic E-layers of finite horizontal dimensions is accepted. Currents in two horizontal E
s
-layers and field-aligned currents connecting the borders of these two layers are considered. The Hall currents in sporadic layers can be strong enough to generate Farley-Buneman turbulence. Some heating effects of local electric fields and the effects on the electron distribution function are found which cause effective excitation of some ionosphere neutral components.Published from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 39, No. 2, pp. 241–249, February, 1996. 相似文献
8.
V. L. Frolov V. V. Chugurin G. P. Komrakov N. A. Mityakov E. N. Myasnikov V. O. Rapoport E. N. Sergeev V. P. Uryadov F. I. Vybornov V. A. Ivanov V. V. Shumaev A. M. Nasyrov I. A. Nasyrov K. M. Groves 《Radiophysics and Quantum Electronics》2000,43(6):446-468
Experimental studies of the features of artificial ionospheric turbulence was performed at the “Sura” heating facility in
August 1998 using numerous diagnostic tools, such as scintillation, chirp-sounding, backscattering, and stimulated electromagnetic
emission (SEE) measurements, as well as sounding a HF-disturbed volume (DV) by probing waves. It has been found that generation
of strong artificial large-scale irregularities (ALSIs), which manifest themselves through the F-spread on ionograms, scintillations
of the satellite signal propagated through the DV, and amplitude fluctuations of the probing wave sounding the DV, is observed
not only for an overdense heating, at fo≤foF2, but also at higher frequencies fo>foF2≥f
uh
(here fo is the pump-wave frequency, foF2 is the critical frequency of the F2-layer for O-mode electromagnetic wave, and f
uh
is the plasma frequency at the upper-hybrid resonance height). This means that transfer of the pump-wave energy in the plasma
due to the development of thermal parametric (resonance) instability, rather than thermal self-focussing instability, plays
the key role in the ALSI generation in the case where the O-mode HF wave is used for the overdense heating. This conclusion
is also confirmed by the fact that the ALSI generation is suppressed in the gyroharmonic frequency range, which is similar
to the well-studied quenching of the downshifted maximum (DM) in SEE spectra. In this paper, we discuss new ALSI features
revealed by the measurements, as well as the limits by which one can control the ALSI spectrum using complex pumping schemes.
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 43, No. 6, pp. 497–519, June, 2000. 相似文献
9.
Ken Takayama Senri Soma Taiji Inoue Hideaki Kakinuma Takashi Haraguchi Kaoru Suzuki 《Applied Physics A: Materials Science & Processing》2010,101(4):727-733
Phosphorus-doped diamond-like carbon (DLC) films were deposited on quartz and p-type silicon (p-Si) substrates by pulsed-laser
deposition. Open-circuit voltage (V
oc) and short-circuit density (I
sc/cm2) from a heating process converted from one type of electrode to another and the two types of electrode pattern are shown
by the V–I characteristics. The first heating process was by a ceramic heater, and the other was by an infrared heater. We adopted two
electrode patterns, from a bipectinate electrode and a plot pattern electrode, to measure electric photovoltaic characteristics.
We were able to upgrade V
oc and I
sc/cm2 to 35∼45 mV, and 0.24 μA/cm2, respectively, under infrared heating. V
oc by the plot pattern electrode was over 2 V under infrared heating and ceramic heating did not match this on deposition by
the PLD method. 相似文献
10.
S. M. Grach E. N. Sergeev V. A. Yashnov P. V. Kotov 《Radiophysics and Quantum Electronics》2008,51(7):499-514
Alternative mechanisms of generation of the stimulated electromagnetic emission (SEE) excited in the ionosphere by high-power
radio waves are analyzed on the basis of measurements of the SEE spectra obtained during the pump-wave frequency sweeping
near the forth (n = 4) and fifth (n = 5) harmonics of the electron gyrofrequency nfce [1] and their comparison with the existing physical models. A method for determination of the magnetic field strength and plasma
density near the double-resonance region in the ionosphere is developed. It is shown that the generation of the broad upshifted
maximum (BUM) feature in the SEE spectrum should occur several kilometers below the double-resonance altitude. A role of high-frequency
plasma modes and small-scale magnetic field-aligned irregularities, excited under ionosphere pumping by a high-power radio
wave, in the formation of SEE spectra is demonstrated. It is shown that the difference in the emission intensities for f0 ≲ nfce and f0 > nfce is related to different regions (altitudes) at which the plasma waves exist in these cases.
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 51, No. 7, pp. 553–570, July 2008. 相似文献
11.
S. S. Matyugov O. I. Yakovlev V. A. Anufriev 《Radiophysics and Quantum Electronics》2008,51(3):161-169
We analyze characteristics of sporadic layers in the equatorial ionosphere using the results of radio occultation sounding
on the paths between GPS satellites and the CHAMP low-orbiting satellite during the solar flare in October–November 2003.
Variations in the amplitude and phase of signals during the lower-ionosphere sounding are studied. It is shown that the use
of amplitude and phase data allows one to obtain parameters of the sporadic ionospheric structures. The data on the occurrence
frequency, height, thickness, and intensity of the Es layers in the daytime and nighttime equatorial ionosphere are presented.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 51, No. 3, pp. 181–190, March 2008. 相似文献
12.
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
13.
Dielectric relaxation measurements of formamide (FMD)-N,N-dimethylaminoethanol (DMAE) solvent mixtures have been carried out over the entire concentration range using time domain
reflectometry technique at 25, 35 and 45°C in the frequency range of 10 MHz to 20 GHz. The mixtures exhibit a principle dispersion
of the Davidson-Cole relaxation type at microwave frequencies. Bilinear calibration method is used to obtain complex permittivity
ɛ*(ω) from complex reflection coefficient ρ*(ω) over the frequency range of 10 MHz to 10 GHz. The excess permittivity (ɛ
E), excess inverse relaxation time (1/τ)E, Kirkwood correlation factor (g
eff), activation energy and Bruggeman factor (f
B) are also calculated to study the solute-solvent interaction.
相似文献
14.
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
15.
V. L. Frolov D. I. Nedzvetsky G. P. Komrakov 《Radiophysics and Quantum Electronics》2005,48(9):661-672
We present the results of measuring the characteristics of the stimulated electromagnetic emission (SEE) of the ionosphere
with variation in the zenith angle of a pump beam of high-power O-mode radio waves in the geomagnetic-meridian plane. The
experiments were performed at the midlatitude heating facility “Sura.” It is established that the maximum intensity of the
DM and BC components of SEE is observed for southward inclination angles θ ≈ 8°--12° of the antenna beam, for which the most
intense generation of artificial small-scale ionospheric irregularities also takes place. Based on the results of measurements
near the fourth and fifth harmonics of the electron gyrofrequency, it is found that the first component of the BUM (BUM-1)
is generated only when the pump wave reaches the plasma-resonance region. This allows one to assume that, unlike the second
component of the BUM (BUM-2), whose generation is determined by development of instability in the upper-hybrid resonance region,
the BUM-1 generation mechanism should be related to processes of interaction between a high-power radio wave and the plasma
in the plasma-resonance region.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 48, No. 9, pp. 743–756, September 2005. 相似文献
16.
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
17.
V. L. Frolov D. I. Nedzvetsky E. N. Sergeev E. A. Shorokhov P. Stubbe 《Radiophysics and Quantum Electronics》2005,48(12):901-918
We present the results of experimental studies of the properties of the thermal narrow-continuum component NCth of stimulated electromagnetic emission (SEE) of the ionosphere observed in a narrow region between the pump frequency and
the downshifted maximum (DM). Spectral and dynamic characteristics of the NCth component are considered and the dependence of its properties on the frequency and power of the pumping wave as well as on
the zenith angle of a high-power radio-wave beam in the geomagnetic-meridian plane is analyzed. It is proved that the NCth generation is determined by the thermal (resonant) parametric instability near the level of the upper-hybrid resonance for
a high-power radio wave. New experimental data on the properties of the main DM thermal component in the spectrum of stimulated
electromagnetic emission, which we used as the reference component in most measurements, are presented.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 12, No. 48, pp. 1013–1032, December 2005. 相似文献
18.
M. A. Bolshov Y. A. Kuritsyn V. V. Liger V. R. Mironenko S. B. Leonov D. A. Yarantsev 《Applied physics. B, Lasers and optics》2010,100(2):397-407
A tunable diode laser absorption spectroscopy (TDLAS) technique and appropriate instrumentation was developed for the measurement
of temperature and water vapor concentrations in heated gases. The technique is based on the detection of the spectra of H2O absorption lines with different energies of low levels. The following absorption lines of H2O were used: 7189.344 cm−1 (E″=142 cm−1), 7189.541 cm−1 (E″=1255 cm−1), 7189.715 cm−1 (E″=2005 cm−1). Spectra were recorded using fast frequency scanning of a single distributed feedback (DFB) laser. A unique differential
scheme for the recording of the absorption spectra was developed. An optimal technique for fitting the experimental spectra
was developed. 相似文献
19.
The crystallization and glass transition kinetics using differential scanning calorimetry (DSC) in 50AgI–33.33Ag2O–16.67[(V2O5)1−x
–(MoO3)
x
] superionic glassy system is discussed. Thermal stability of glass, studied using various criteria, does not vary significantly
with glass former variation. However, the activation energies for structural relaxation (E
s) at glass transition temperature and crystallization (E
c) obtained using Moynihan and Kissinger, Matusita-Sakka formulations found to exhibit interesting trends with MoO3 substitution in the glass matrix. It is noticed that the electrical conductivity (σ)–temperature (T) cycles obtained at a typical heating rate of 1 °C/min do exhibit significant thermal events. The conductivity after first
heating cycle at room temperature is found to be increasing with MoO3 content and maximum for x = 0.3 (~10−3 Ω−1 cm−1 at 30 °C) which is comparable to that of the host 50AgI–33.33Ag2O–16.67V2O5 glassy system. The parameters obtained from σ–T plots and DSC scans do complement each other in a particular range of composition. 相似文献
20.
NaAgPbP2O7 was prepared with a solid-state reaction. The electrical properties were investigated by using impedance measurements in
the frequency range from 200 Hz to 5 MHz with the TEGAM 3550 ALF automatic bridge monitored by a microcomputer between 581 K
and 703 K. The Z′ and Z″ versus frequency plots are well fitted to an equivalent circuit model. The conductivity data obey the universal power law.
The conductivity in the material is due to the hopping of monovalent ions parallel to (001) plane. 相似文献