排序方式: 共有15条查询结果,搜索用时 15 毫秒
1.
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
2.
3.
We consider the problem of three-dimensional diffraction of electromagnetic waves excited by an elementary source on a chiral
infinite cylinder of arbitrary radius. Effective scattering cross sections of a chiral cylinder in the case of two-dimensional
diffraction are numerically analyzed.
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 51, No. 10, pp. 872–883, October 2008. 相似文献
4.
We consider diffraction of electromagnetic waves by an anisotropic cylindrical inhomogeneity located in a planar waveguide
with perfectly conducting walls. Anisotropy is allowed for by using the uniaxial-crystal approximation. A rigorous analytical
solution is represented in the form of double sums over eigenfunctions of a planar waveguide with perfectly conducting walls
and azimuthal eigenfunctions of a cylinder. Different components of the intensity of the electric field scatttered by an anisotropic
inhomogeneity are numerically calculated. The influence of the anisotropy and sizes of the inhomogeneity on the scattered
field is analyzed.
__________
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 48, No. 7, pp. 605–615, July 2005. 相似文献
5.
6.
V. L. Frolov E. N. Sergeev B. Thide E. A. Shorokhova 《Radiophysics and Quantum Electronics》2005,48(2):98-119
We present the results of experiments on modification of the ionospheric F region by two high-power (Peff 20 MW) O-mode electromagnetic waves. The experiments were performed at the Sura heating facility of the Radiophysical Research Institute (Nizhny Novgorod, Russia) in May 23–27, 1993 at the pump frequencies near the 4th, 5th, or 6th harmonics of the electron gyrofrequency. Ionospheric perturbations were diagnosed by measuring the stationary spectral characteristics of the stimulated electromagnetic emission (SEE) of the ionospheric plasma. We determine the features of variation in the spectral characteristics of particular SEE components during the simultaneous heating of the ionospheric plasma by two radio waves in comparison with the case of a monochromatic pump wave. We observed the effect of enhanced generation of the broad up-shifted maximum (BUM) by the higher-frequency pump wave. This is accompanied by strong suppression of the BUM induced by the lower-frequency pump wave. It is shown that the effects observed during the two-frequency heating of the ionosphere have well pronounced gyroharmonic properties, i.e., depend on both the electron-gyroharmonic number and the frequency detuning of the pump waves from a harmonic of the electron gyrofrequency. We also pointed out that a change in the properties of artificial small-scale ionospheric irregularities (striations) excited by high-power radio waves is not the cause of a change in the properties of the down-shifted maximum and the BUM during the two-frequency modification of the ionospheric plasma. Ways for the further development of these studies are discussed.__________Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 48, No. 2, pp. 110–133, February 2005. 相似文献
7.
D. A. Zuev A. A. Lotin O. A. Novodvorsky A. V. Shorokhova O. D. Khramova 《Bulletin of the Russian Academy of Sciences: Physics》2012,76(10):1119-1122
The possibilities for applying lasers to the fabrication of solar cells (the laser texturing of silicon surfaces and pulsed laser deposition of indium tin oxide (ITO) thin films) are demonstrated. 相似文献
8.
We present the results of numerical simulation of scattering of millimeter electromagnetic waves from a statistically rough
earth surface by the methods of small perturbations and tangent surfaces. We develop numerical algorithms and codes for (i)
calculation of the specific effective area of scattering from small-scale, large-scale, and combined (two-scale) structures
of land-surface irregularities and (ii) calculation of the field scattered from a rough surface with allowance for the antenna
pattern. As an example, we present the results of numerical calculation of the specific effective area of scattering and the
scattered field for the case of the Gaussian single-lobe antenna pattern and a land-surface model (asphalt, concrete, sand,
and snow) in the form of a periodic structure. The theoretical results obtained for the specific effective area scattering
are in good agreement with the experimental data.
__________
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 48, No. 6, pp. 478–487, June 2005. 相似文献
9.
V. L. Frolov G. P. Komrakov D. I. Nedzvetsky V. O. Rapoport E. N. Sergeev E. A. Shorokhova P. Stubbe 《Radiophysics and Quantum Electronics》2006,49(8):579-596
We report on the results of studies of the evolution of artificial ionospheric turbulence (AIT) excited by short pulses of
high-power short-wave O-mode radio emission in the ionospheric F region. On the basis of the obtained experimental data, it
is assumed that the streams of thermal and suprathermal electrons generated in the regions of resonant interaction between
a high-power radio wave and the plasma and propagating along the geomagnetic field stimulate the development of plasma perturbations
far away from the primary-turbulence regions. Specific features of the measurement procedure are considered, an empirical
model of the observed phenomena is developed, and possible problems in the further studies are outlined.
__________
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 49, No. 8, pp. 643–663, August 2006. 相似文献
10.