Нижний Новгород, Россия
Нижний Новгород, Россия
We have experimentally studied the influence of the local ionosphere, namely the ionospheric Alfvén resonator (IAR) and the lower ionospheric resonator at altitudes 80–300 km (sub-IAR) on the amplitude and polarization of the first Schumann resonance. The study is based on spectral analysis of data from simultaneous monitoring of ULF magnetic noise components at a meridional chain of stations: high-latitude stations Barentsburg and Lovozero, mid-latitude observatory NNGU NIRFI (NL, Nizhny Novgorod Region), a low-latitude station in Israel. We have also used monitoring data from the Borok and Crete observatories. At the stations in dark conditions, significant variations were found in the spectrum of the polarization parameter ε at the frequency of the first Schumann resonance (SR). Moreover, these variations had different character at different observatories. Analysis of the daily dynamics of the parameter ε has shown that these variations are associated with the influence of local sub-IAR having different optical thickness and quality factor at these observatories. The influence of sub-IAR on polarization in the SR band was found to depend on the ratio of the boundary frequency fb (the frequency that separates the negative and positive polarization of ULF magnetic noise) to the frequency of the first SR. The IAR influence on the polarization and amplitude of magnetic fields in the frequency band of the first Schumann resonance was discovered only at the NL and Lovozero stations: a high-quality Alfvén resonator in the ionosphere above the NL station could cause the SR frequency band to change and its central frequency to shift. Analysis of low-frequency data from the observatories separated by distances of 400 km has revealed that the influence of local ionospheric resonators can lead to a difference in the amplitude characteristics of the first SR even at such distances. It has also been shown that the influence of the IAR and sub-IAR resonators on the azimuthal angle of the magnetic field vector in the frequency band of the first SR is less noticeable and can generate variations in this parameter by 10°–20°. Numerical calculations performed for the spherical waveguide model made it possible to adequately interpret the features of the daily dynamics of the parameter ε in the frequency range of the first SR.
ionospheric resonators,magnetic noise, Schumann resonance, polarization, spectral parameters, resonance spectral structure
1. Belyaev P.P., Polyakov S.V., Rapoport V.O., Trakhtengerts V.Yu. Detection of the resonant structure of the spectrum of the atmospheric electromagnetic noise background in the range of short-period geomagnetic pulsations. Doklady AN SSSR [Reports of the Academy of Sciences of the USSR]. 1987, vol. 297, pp. 840–843. (In Russian).
2. Belyaev P.P., Polyakov C.V., Rapoport V.O., Trakhtengerts V.Yu. Experimental studies of the spectral resonance structure of the atmospheric electromagnetic noise background within the range of short-period geomagnetic pulsations. Radiophys. Quantum Electron. 1989, vol. 32, no 6, pp.491–501. DOI:https://doi.org/10.1007/BF01058169.
3. Bosinger T., Demekhov A.G., Ermakova E.N., Haldoupis C., Zhou Q. Pulsating nighttime magnetic background noise in the upper ULF band at low latitudes, J. Geophys. Res.: Space Phys. 2014, vol. 119, no. 5, pp. 4109–4119. DOI: 10.1002/ 2014ja019906.
4. Bösinger T., Shalimov S.L. Dispersive changes in magnetic background noise polarization at 0.1 to 6 Hz during sunset and sunrise at L=1.3, Ann. Geophys. 2004, vol. 22, no. 6, pp. 1–12. DOI:https://doi.org/10.5194/angeo-22-1989-2004.
5. Ermakova E.N., Kotik D.S., Polyakov S.V., Shennikov A.V. On a mechanism forming a broadband maximum in the spectrum of background noise at frequencies 2–6 Hz. Radiophys. Quantum Electron. 2007, vol. 50, no7, pp. 555–569. DOI:https://doi.org/10.1007/s11141-007-0049-1.
6. Ermakova E.N., Polyakov S.V., Semenova N.V. A study of resonance structures with different scales in the spectrum of background extremely low frequency noise at middle latitudes. Radiophys. Quantum Electron. 2011, vol. 54, no. 12, pp. 796–804. DOI:https://doi.org/10.1007/s11141-012-9341-9.
7. Ermakova E.N., Kotik D.S., Ryabov V.A., Bosinger T., Zhou K. Studying the variations of the broadband spectral maximum parameters in the natural ULF fields. Radiophys. Quantum Electron. 2012, vol. 55, no. 10-11, pp. 605–615. DOI:https://doi.org/10.1007/s11141-013-9398-0.
8. Ermakova E.N., Kotik D.S., Ryabov A.V., Panyutin A.A. Studying the effect of the local thunderstorm cells on the background ULF magnetic noise parameter spectra. Radiophys. Quantum Electron. 2014, vol. 57, no. 11, pp. 782–794. DOI:https://doi.org/10.1007/s11141-015-9564-7.
9. Greenberg E., Price C. Diurnal variations of ELF transients and background noise in the Schumann resonance band. Radio Sci. 2007, vol. 42, RS2S08, pp. 1–14. DOI: 10.1029/ 2006RS003477.
10. Kirillov V.V., Kopeykin V.N. Solving a two-dimensional telegraph equation with anisotropic parameters. Radiophys. Quantum Electron. 2002, vol. 45, no. 12, pp. 929–941. DOI:https://doi.org/10.1023/A:1023525331531.
11. Kirillov V.V., Kopeykin V.N. Formation of a resonance structure of the local inductance of the ionosphere at frequencies 0.1–10 Hz. Radiophys. Quantum Electron. 2003, vol. 46, no. 1, pp. 1–12. DOI:https://doi.org/10.1023/A:1023652610575.
12. Koloskov A.V., Bezrodny V.G., Budanov O.V., Paznukhov A.V., Yampolsky Yu.M. Polarization monitoring of Schumann resonances in Antarctica and restoration of the characteristics of global thunderstorm activity. Radiofizika i radioastronomiya. [Radiophysics and Radioastronomy]. 2005, vol. 10, no. 1, pp. 11–29. (In Russian).
13. Nickolaenko A.P., Rabinowicz L.M. Study of the annual changes of global lightning distribution and frequency variations of the first Schumann resonance mode. J. Atmos. Solar-Terr. Phys. 1995, vol. 57, no. 11, pp. 1345–1348. DOI:https://doi.org/10.1016/0021-9169(94)00114-4.
14. Nickolaenko A.P., Satori G., Zieger B., Rabiniwicz L.M., Kudintseva I.G. Parameters of global thunderstorm activity deduced from long-term Schumann resonance records. J. Atmos. Solar-Terr. Phys. 1998. vol. 60, no. 3, pp. 887–399. DOI:https://doi.org/10.1016/S1364-6826(97)00121-1.
15. Ogawa T., Tanaka Y., Yasuhara M. Schumann resonances and world-wide thunderstorm activity—diurnal variations of the resonant power of natural noises in the earth-ionosphere cavity. J. Geophys. Res. 1969, vol. 21, no. 1, pp. 447–452.
16. Polyakov S.V., Rapoport V.O. Ionospheric Alfven resonator. Geomagnetizm i aeronomiya [Geomagnetism and Aeronomy]. 1981, vol. 21, no. 5, pp. 816–822. (In Russian).
17. Potapov A., Polyushkina T.N., Tsegmed B. Morphology and diagnostic potential of the ionospheric Alfvén resonator. Solar-Terrestrial Phys. 2021, vol. 7, no. 3, pp. 39–56. DOI:https://doi.org/10.12737/stp-73202104.
18. Price C., Melnikov A. Diurnal, seasonal and inter-annual variations in the Schumann resonance parameters. J. Atmos. Solar-Terr. Phys. 2004, vol. 66, no. 13-14, pp. 1179–1185. DOI:https://doi.org/10.1016/j.jastp.2004.05.004.
19. Roldugin V.K., Vasiliev A.N. Variations in the parameters of the Schumann resonance polarization ellipse in the horizontal and vertical planes according to observations at the Barentsburg and Lovozero observatories. Geomagnetizm i aeronomiya [Geomagnetism and Aeronomy]. 2012, vol.52, no.1, pp. 73-81. (In Russian).
20. Roldugin V.C., Maltsev Y.P., Vasiljev A.N., Schokotov A.Y., Belyajev G.G. Diurnal variations of Schumann resonance frequency in NS and EW magnetic components. J. Geophys. Res. 2004, vol. 109, A08304, pp. 1–4. DOI:https://doi.org/10.1029/2004JA010487.
21. Rusakov N.N., Bakastov S.S. Rotation of the horizontal projection of the magnetic field disturbance vector at Schumann resonance frequencies. Geomagnetizm i aeronomiya [Geomagnetism and Aeronomy]. 1988, vol. 28, no. 6, pp. 919–922. (In Russian).
22. Satori G., Zieger B. Spectral characteristics of Schumann resonances observed in Central Europe. J. Geophys. Res. 1996, vol. 101, no. D23, pp. 29663–29669. DOI:https://doi.org/10.1029/96JD00549.
23. Schlegel K., Fullekrug M. Diurnal harmonics in Schumann resonance parameters observed on both hemispheres. Geophys. Res. Lett. 2000, vol. 27, no. 17, pp. 2805–2808. DOI:https://doi.org/10.1029/2000GL003774.
24. Sentman D.D. Magnetic elliptical polarization of Schumann resonances. Radio Sci. 1987, vol. 22, no. 4, pp. 595–606. DOI:https://doi.org/10.1029/RS022i004p00595.
