Impact of a Strong Magnetic Storm and Two X-Ray Flares on the Ionospheric HF Channel in the Summer Solstice of 2015 According to Oblique Sounding in the Eurasian Region
| Autor: | V. P. Uryadov, A. G. Chernov, A. A. Kolchev, G. G. Vertogradov, I. A. Egoshin, F. I. Vybornov, V. V. Shumaev, M. S. Sklyarevsky |
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| Rok vydání: | 2017 |
| Předmět: |
Physics
Geomagnetic storm Nuclear and High Energy Physics 010504 meteorology & atmospheric sciences Astronomy and Astrophysics Statistical and Nonlinear Physics Geophysics Atmospheric sciences Sporadic E propagation 01 natural sciences F region Physics::Geophysics Electronic Optical and Magnetic Materials Depth sounding Middle latitudes Physics::Space Physics 0103 physical sciences Solstice Electrical and Electronic Engineering Ionosphere 010303 astronomy & astrophysics 0105 earth and related environmental sciences Radio wave |
| Zdroj: | Radiophysics and Quantum Electronics. 60:355-373 |
| ISSN: | 1573-9120 0033-8443 |
| DOI: | 10.1007/s11141-017-9806-y |
| Popis: | We present the results of observations of the impact a strong magnetic storm and two X-ray flares in the summer solstice of 2015 on the HF signal characteristics during oblique sounding of the ionosphere in the Eurasian region. It was found that the negative phase of the magnetic storm led to a strong degradation of the ionospheric channel, up to a long blackout on the paths adjacent to the subauroral latitudes. On the midlatitude paths, a decrease in the maximum observable frequency of the F layer reached 50% with respect to the average values for an undisturbed ionosphere. The propagation velocity of the negative phase of a disturbance from the subauroral to the midlatitude ionosphere is determined (it is equal to about 100 m/s). It is shown that during a magnetic storm the least observable frequency and the average signal-to-noise ratio for the propagation mode via the sporadic E s layer correlate well with the auroral AE index. Anomalous signals were detected in the main phase of the magnetic storm on the Cyprus—Rostov-on-Don path when a chirp ionosonde–radio direction finder was operated in the over-the-horizon HF radar mode. On the basis of modeling and comparison with experimental data, it is shown that the anomalous signals are due to scattering of radio waves by small-scale irregularities located in the subauroral ionospheric F region. |
| Databáze: | OpenAIRE |
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