Low-Frequency Electromagnetic Oscillations of the Earth-Ionosphere Cavity

Madden, T.; Thompson, W.

doi:10.21236/ad0607080

Cited by 16 publications

(28 citation statements)

References 6 publications

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“…The Schumann resonance is of the global nature, and only powerful large‐scale ionospheric perturbations are capable to influence the resonance frequencies (see assessments and simulation results given by Madden and Thompson [1965] and Bliokh [1980]). Good temporal correspondence of very energetic proton invasions with the SR parameters testifies that a solar proton event can be one of such phenomena.…”

Section: Discussionmentioning

confidence: 99%

Changes of Schumann resonance parameters during the solar proton event of 14 July 2000

et al. 2003

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[1] The ELF measurements in Russian observatories Lovozero (the Kola Peninsula) and Lekhta (Karelija) during the solar proton event of 14 July 2000 show the decrease of frequencies of the first and second Schumann resonance modes of $0.4 Hz and the increase of the first-mode bandwidth from 0.8 to 1.5 Hz. The solar X-ray burst, preceding the proton precipitation, is accompanied by the increase of the first-mode frequency. Approximate formulas for frequencies and qualities of the two first modes are found for a two-layer model of the Schumann resonator (SR). The changes of the SR parameters are a response of the Earth-ionosphere resonator to large-scale disturbances of the polar ionosphere.

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Section: Discussionmentioning

confidence: 99%

Changes of Schumann resonance parameters during the solar proton event of 14 July 2000

et al. 2003

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“…The meaning of the Q of a system is a matter of definition. To the Earth‐ionosphere cavity various definitions of Q were applied [ Galejs , 1965, 1972; Jones , 1964, 1967; Madden and Thompson , 1965; Tran and Polk , 1979]. The rigorous definition involving the rate of energy dissipation at the given resonance mode n is not amenable to direct observation especially in continually excited systems.…”

Section: Q Parameter Discussionmentioning

confidence: 99%

“…In the 2‐D approach the wave propagation is described by the telegraph equation that relates voltages u and currents i within the transmission line of spherical shape. [ Madden and Thompson , 1965; Zahn , 1979]. Reducing 3‐D waveguide to 2‐D transmission line leads to the loss of some physical information, but at any time one can return from circuit variables u ( x , y , t ) and i ( x , y , t ) to the field variables E ( x , y , z , t ) and B ( x , y , z , t ) if only the detailed structure of the Earth‐ionosphere waveguide is known.…”

Section: Tdte Model Of the Global Resonatormentioning

confidence: 99%

“…Our approach of seeking TDTE solutions, needed further for SR modeling, uses the method of finite elements in which, after covering the sphere with a two‐dimensional transmission line, the numerical code for analysis of a transmission line network is applied. One possible way of covering the sphere with 2‐D line is through making an orthogonal grid of parallels and meridians and connecting its nodes with 1‐D transmission lines [ Madden and Thompson , 1965]. That way we obtain the elements of 2‐D line having extent w Θ × w Φ .…”

Section: Tdte Model Of the Global Resonatormentioning

confidence: 99%

“…In numerous but already classical papers, it was shown that the knowledge of a conductivity‐height profile for the two lower layers of the ionosphere, the D and E layers, allows proper reconstruction of the fundamental properties of the Schumann resonances [ Wait , 1960, 1970; Galejs , 1961, 1962, 1965, 1972; Jones , 1964, 1967; Chapman and Jones , 1964; Chapman et al , 1966; Bliokh et al , 1977; Greifinger and Greifinger , 1978, 1979; Tran and Polk , 1979; Sentman , 1983, 1990; Sentman and Fraser , 1991]. As the natural mechanism of the ELF field propagation in the global resonator is two‐dimensional, Madden and Thompson [1965] proposed a model in which the two‐dimensional telegraph equation was used. The computations in their study were performed by solving a two‐dimensional network that was the lumped circuit representation of the transmission‐surface equations.…”

Section: Introductionmentioning

confidence: 99%

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Solar variations in extremely low frequency propagation parameters: 1. A two‐dimensional telegraph equation (TDTE) model of ELF propagation and fundamental parameters of Schumann resonances

et al. 2003

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[1] The primary purpose of the research presented is to study solar variations in extremely low frequency (ELF) propagation parameters using Schumann resonance (SR) data from our irregular observations carried out in the East Carpathian mountains. The natural electromagnetic ELF fields in the Earth-ionosphere cavity (the global resonator) are strongly dependent on its resonance and propagation properties as well as on the global thunderstorm activity. Thus a determination of the global resonator parameters from Schumann resonances needs information about such signal properties, which depend only on physical conditions of the Earth-ionosphere cavity. To seek such signal properties, we consider the two-dimensional telegraph equation (TDTE) approach for describing propagation of ELF electromagnetic waves in a two-dimensional spherical transmission line model of the Earth-ionosphere cavity. We have set up a model consisting of a network of finite, homogeneous, one-dimensional transmission lines covering the sphere; with the square root dependence of the attenuation rate from frequency as a sufficient model for the study of the solar influence on global properties of the Earth-ionosphere cavity. Using this model, we have constructed useful formulae and algorithms connecting the observed parameters of Schumann resonances with the attenuation rate. This enables us to study the solar influence on the attenuation rate from diurnal observations of the NS-magnetic component of the ELF field measured at one station. As the measurements were carried out during both the minimum and the maximum of the solar cycle 23, we present in the work of KuÀ lak et al. [2003] evidence for a change in the ELF attenuation rate in the Earth-ionosphere cavity with solar activity.

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Application of the Schumann resonance spectral decomposition in characterizing the main African thunderstorm center

et al. 2014

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In this paper we present a new method for quantifying the main tropical thunderstorm regions based on extremely low frequency (ELF) electromagnetic wave measurements from a single station-the Hylaty ELF station in Central Europe. Our approach is based on Schumann resonance (SR) measurements, which we apply as an example to thunderstorms in Africa. By solving the inverse problem, using the SR power spectrum templates derived analytically, we calculate distances to the most powerful thunderstorm centers and present simplified 1-D thunderstorm lightning activity "maps" in absolute units C 2 m 2 /s. We briefly describe our method of SR power spectrum analysis and present how this method is used with real observational data. We obtained the monthly lightning activity maps of the African storm centers with a spatial resolution of 1 • and temporal resolution of 10 min for January and August 2011. This allowed us to study the varying location and intensities of the African storm centers in different seasons of the year. A cross check of the obtained lightning activity maps with Tropical Rainfall Measuring Mission satellite data recorded by the Lightning Imaging Sensor and the derived correlation coefficients between SR and optical data were used to validate the proposed method. We note that modeling a maximum possible number of resonance modes in the SR power spectra (in our case, seven resonances) is essential in application of the proposed approach.

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Low-Frequency Electromagnetic Oscillations of the Earth-Ionosphere Cavity

Cited by 16 publications

References 6 publications

Changes of Schumann resonance parameters during the solar proton event of 14 July 2000

Changes of Schumann resonance parameters during the solar proton event of 14 July 2000

Solar variations in extremely low frequency propagation parameters: 1. A two‐dimensional telegraph equation (TDTE) model of ELF propagation and fundamental parameters of Schumann resonances

Application of the Schumann resonance spectral decomposition in characterizing the main African thunderstorm center

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