Search results for "Ionosphere"
showing 10 items of 19 documents
A 3-Year Sample of Almost 1,600 Elves Recorded Above South America by the Pierre Auger Cosmic-Ray Observatory
2020
The time and location of the 1,598 verified and reconstructed elves, used for the analysis showcased in this paper, are publicly available on the website of the Pierre Auger Observatory (https://www.auger.org/ index.php/science/data). We wish to thank the World Wide Lightning Location Network (http://wwlln.net), a collaboration among over 50 universities and institutions, for providing the lightning location data used in this paper. We acknowledge Robert Marshall for providing one of the most advanced elve simulations to the public, a key tool in understanding the elves observed by the Pierre Auger Observatory. The successful installation, commissioning, and operation of the Pierre Auger Ob…
Innovative technical implementation of the Schumann resonances and its influence on organisms and biological cells
2019
Over the course of time in the digital age, oscillating processes were utilized in various realizations. Life without these became hardly imaginable. Schumann resonances are electromagnetical resonances or eigenfrequencies (radio waves), which originate from the oscillation in a hollow space shell. Their average basic frequency is 7,83Hz. The above-mentioned radio waves emerge from energy discharges such as thunderstorms, lightning or solar wind within the earth's surface and the ionosphere. They exist around the globe. Various scientists have discovered a correlation to our health on the basis of studies and experiments; their absence can result in a variety of disorders from headaches to …
Sun-Earth System Interaction studies over Vietnam: an international cooperative project
2006
International audience; During many past decades, scientists from various countries have studied separately the atmospheric motions in the lower atmosphere, in the Earth's magnetic field, in the magnetospheric currents, etc. All of these separate studies lead today to the global study of the Sun and Earth connections, and as a consequence, new scientific programs (IHY- International Heliophysical Year, CAWSES- Climate and Weather in the Sun-Earth System) are defined, in order to assume this new challenge. In the past, many scientists did not have the possibility to collect data at the same time in the various latitude and longitude sectors. Now, with the progress of geophysical sciences in …
An analysis of VLF electric field spectra measured in Titan's atmosphere by the Huygens probe
2009
[1] A numerical simulation of Titan's electromagnetic cavity in the VLF band is carried out using the Transmission Line Matrix (TLM) method, with the aim of assessing the VLF electric field spectra sent by the Huygens probe. In an Earth-like model, successive peaks would be expected in the spectra, associated with multiple reflections of the electromagnetic wave on the external surfaces of Titan's electromagnetic cavity, formed by the ionosphere and a conductive ground or underground surface. However, owing to high losses conferred by the electrical conductivity to Titan's atmosphere, the direct numerical and experimental spectra are decreasing functions of the frequency without resonances …
A numerical study of atmospheric signals in the Earth-ionosphere electromagnetic cavity with the Transmission Line Matrix method
2006
[1] The effect of the Earth-ionosphere electromagnetic cavity on the spectrum of an atmospheric signal generated by a broadband electrical current source is analyzed numerically by means of the Transmission Line Matrix (TLM) method. Two new TLM meshes are developed, one with transmission lines connected in parallel and the other with connections in series. The equations describing propagation through these parallel or series meshes are equivalent to the Maxwell equations for TEr or TMr modes in the spherical Earth-ionosphere cavity, respectively. The numerical algorithm obtains Schumann resonance frequencies very close to the experimental ones, confirming that this methodology is a valid nu…
Numerical analysis of ionosphere disturbances and Schumann mode splitting in the Earth-ionosphere cavity
2008
[1] The variability of ionosphere properties plays an important role in the Schumann resonances (SR), amplitudes, frequencies, and Q factor. Therefore, as atmosphere ionization is related to solar activity, SR could be devised as a source of indirect parameters that locally from the surface of the Earth could provide space weather information. A proper understanding of this link to SR parameters can be obtained through finite difference time domain (FDTD) simulations, specifically with the numerically obtained modes and frequencies that relate frequency shifts to the day-night asymmetry and polar inhomogeneities. Day-Night asymmetry is observed to have a minor influence in SR; however, larg…
Unusually high frequency natural VLF radio emissions observed during daytime in Northern Finland
2016
Geomagnetic field variations and electromagnetic waves of different frequencies are ever present in the Earth's environment in which the Earth's fauna and flora have evolved and live. These waves are a very useful tool for studying and exploring the physics of plasma processes occurring in the magnetosphere and ionosphere. Here we present ground-based observations of natural electromagnetic emissions of magnetospheric origin at very low frequency (VLF, 3–30 kHz), which are neither heard nor seen in their spectrograms because they are hidden by strong impulsive signals (sferics) originating in lightning discharges. After filtering out the sferics, peculiar emissions are revealed in these dig…
A numerical study of the Schumann resonances in Mars with the FDTD method
2007
[1] Natural electromagnetic waves generated near the surface by electrostatic discharges in dust storms (dust devils) or by geological activity could be trapped in the resonant cavity formed by the surface and lower ionosphere of Mars, as it occurs on Earth giving rise to Schumann resonances. The finite difference time-domain technique (FDTD) is applied to model the atmosphere of Mars in order to determine Schumann resonant frequencies, and natural electromagnetic fields at the extremely low frequency range (ELF). A numerical tool is provided to analyze the electrical conductivity profile of the Martian atmosphere, with the aim of obtaining Schumann resonance frequencies and their dependenc…
A Review on Multi-GNSS for Earth Observation and Emerging Applications
2022
Global Navigation Satellite System (GNSS) has drawn the attention of scientists and users all over the world for its wide-ranging Earth observations and applications. Since the end of May 2022, more than 130 satellites are available for fully global operational satellite navigation systems, such as BeiDou Navigation Satellite System (BDS), Galileo, GLONASS and GPS, which have been widely used in positioning, navigation, and timing (PNT), e.g., precise orbit determination and location-based services. Recently, the refracted, reflected, and scattered signals from GNSS can remotely sense the Earth’s surface and atmosphere with potential applications in environmental remote sensing. In this pap…