TIC190 - Artículoshttps://hdl.handle.net/10481/529642024-03-29T06:02:49Z2024-03-29T06:02:49ZA 3D TLM code for the study of the ELF electromagnetic wave propagation in the Earth's atmosphereSalinas Extremera, AlfonsoPorti Durán, Jorge AndrésNavarro, Enrique A.Toledo-Redondo, SergioAlbert, InmaculadaCastilla, AidaMontagud-Camps, Víctorhttps://hdl.handle.net/10481/861032023-12-12T09:11:04ZA 3D TLM code for the study of the ELF electromagnetic wave propagation in the Earth's atmosphere
Salinas Extremera, Alfonso; Porti Durán, Jorge Andrés; Navarro, Enrique A.; Toledo-Redondo, Sergio; Albert, Inmaculada; Castilla, Aida; Montagud-Camps, Víctor
The interest in the study of electromagnetic propagation through planetary atmospheres is briefly discussed. Special attention is devoted to extremely-low-frequency fields in the Earth's atmosphere for its global nature and possible applications to climate monitoring studies among others. In the Earth's case, the system can be considered as a spherical electromagnetic shell resonator in which two concentric and large conducting spheres with a radius around 6300 km are separated by a very small distance of around 100 km, the atmosphere height. A numerical solution using the Transmission Line Method is proposed. The classical spherical-coordinate description is easy to use, however, the important difference in the dimensions along the three coordinate directions causes high numerical dispersion in the results. A Cartesian scheme with equal node size for all directions is used to reduce this undesired dispersion. A pre-processing stage is the key point introduced to lessen the resulting high demand of memory and time calculation and make the solution feasible. A parallelized Fortran code together with pre- and post-processing Python programs to ease the user interface are provided with this work. Details on the Fortran code and the Python modules are included both in the paper and the source codes to allow the use and modifications by other researchers interested in electromagnetic propagation through planetary atmospheres. The program allows calculation of the time evolution of the electromagnetic field at any point in the atmosphere. It includes the possibility of considering multiple time-dependent sources and different homogeneous and inhomogeneous conductivity profiles to model different situations. Profiles to study day-night asymmetries or locally perturbed profiles which have been attributed to earthquakes in the literature are implemented, for instance.
Schumann resonance data processing programs and four-year measurements from Sierra Nevada ELF stationSalinas Extremera, AlfonsoRodríguez-Camacho, JesúsPorti Durán, Jorge AndrésCarrión Pérez, María del CarmenFornieles Callejón, Jesús FranciscoToledo-Redondo, Sergiohttps://hdl.handle.net/10481/750942022-05-30T10:36:12ZSchumann resonance data processing programs and four-year measurements from Sierra Nevada ELF station
Salinas Extremera, Alfonso; Rodríguez-Camacho, Jesús; Porti Durán, Jorge Andrés; Carrión Pérez, María del Carmen; Fornieles Callejón, Jesús Francisco; Toledo-Redondo, Sergio
In this work, we present to the scientific community the measurements taken during four years, from March 2013 to February 2017 inclusive, by the Extremely Low Frequency Sierra Nevada station, Spain, together with the data processing programs developed in Python (version 3.8) to extract the Schumann resonance (SR) parameters (i.e., amplitudes, resonant frequencies, resonance widths) in 10 min time periods from these records. The measure- ments correspond to the voltage induced by the atmospheric electromagnetic field at the north-south and east- west oriented magnetometers of the station. The process comprises four stages. The spectrum, calibrated in the frequency band ranging from 6 Hz to 25 Hz, is obtained at the first stage using the Welch method with Hann windows. The second step eliminates the anthropogenic noise generated by different undesired sources. Next, a non-linear fit of the measured spectrum combining Lorentzian functions together with a linear term is carried out in order to identify the presence of SRs and quantitatively characterize them. This third step is carried out using the Python package Lmfit, which implements the Levenberg-Marquad algorithm. Finally, a compact and easy-to- read output is generated at the fourth stage, using the power of the Numpy arrays and the npz format. In addition, four Jupyter notebooks with the description of the code and the possibility of their use in interactive mode are presented as supplementary material with this paper.
Four Year Study of the Schumann Resonance Regular Variations Using the Sierra Nevada Station Ground-Based MagnetometersRodríguez-Camacho, JesúsSalinas Extremera, AlfonsoCarrión Pérez, María del CarmenPorti Durán, Jorge AndrésFornieles Callejón, Jesús FranciscoToledo-Redondo, Sergiohttps://hdl.handle.net/10481/736532022-03-23T07:47:48ZFour Year Study of the Schumann Resonance Regular Variations Using the Sierra Nevada Station Ground-Based Magnetometers
Rodríguez-Camacho, Jesús; Salinas Extremera, Alfonso; Carrión Pérez, María del Carmen; Porti Durán, Jorge Andrés; Fornieles Callejón, Jesús Francisco; Toledo-Redondo, Sergio
We present a study of the Schumann resonance (SR) regular variations (March 2013–February 2017) using the ground-based magnetometers from the Sierra Nevada station, Spain (37°02′N, 3°19′W). The study is based on the fitting parameters obtained by the Lorentzian fit, calculated for each 10-min interval record, namely, peak amplitudes, peak frequencies, width of the resonances, and the power spectrum integral for the first three SR modes. We consider three time-scales in the study: seasonal, monthly, and daily variations. The processed data collected by the Sierra Nevada station are also made public with this work. The general characteristics of the long-term evolution of the SR are confirmed, but discrepancies appear that require further study comparing recent measurements from different stations. Signatures of the influences of the El Niño phenomenon and the solar cycle to SR have been found
Schumann resonances at Mars: Effects of the day-night asymmetry and the dust-loaded ionosphereToledo Redondo, SergioSalinas Extremera, AlfonsoPorti Durán, Jorge AndrésWitasse, O.Cardnell, S.Fornieles Callejón, Jesús FranciscoMolina Cuberos, Gregorio JoséDéprez, G.Montmessin, F.https://hdl.handle.net/10481/582742021-06-15T13:14:40ZSchumann resonances at Mars: Effects of the day-night asymmetry and the dust-loaded ionosphere
Toledo Redondo, Sergio; Salinas Extremera, Alfonso; Porti Durán, Jorge Andrés; Witasse, O.; Cardnell, S.; Fornieles Callejón, Jesús Francisco; Molina Cuberos, Gregorio José; Déprez, G.; Montmessin, F.
Schumann resonances are standing waves that oscillate in the electromagnetic cavity formed
between the conducting lower ionosphere and the surface of the planet. They have been measured in situ
only on Earth and Titan, although they are believed to exist on other planets like Mars. We report numerical
simulations of the Martian electromagnetic cavity, accounting for the day-night asymmetry and different
dust scenarios. It has been found that the resonances are more energetic on the nightside, the first
resonance is expected to be 9–14 Hz depending on the dust activity and to have low quality factors (Q ≃ 2).
This work serves as an input for the upcoming Exomars surface platform (launch 2020), who will attempt to
measure them for the first time.
Owing to the large size of the
dataset, scientists interested in it are
encouraged to contact the authors
directly. The atmospheric properties
used in the present study have been
taken from the Mars Climate Database
http://www-mars.lmd.jussieu.fr/.