Solar storm effects during Saint Patrick's Days in 2013 and 2015 on the Schumann resonances measured by the ELF station at Sierra Nevada (Spain)

Abstract

The effects of solar storms occurring during the days 17 to 19 March 2013 and 2015, St. Patrick's Day intervals, on Schumann resonances (SRs) have been studied. To do this, the experimental data recorded by the Juan Antonio Morente extremely low frequency station located at Sierra Nevada, Spain, have been processed in order to obtain hourly averaged information on the first three resonance modes. Results are compared with monthly averages of the SR data for each hour to detect deviations from the regular behavior. Evidence of significant changes in the peak amplitudes and frequencies of the SRs have been identified in the station's measurements and related to the coronal mass ejection impact in the magnetosphere, detected by in situ plasma measurements onboard spacecraft in the solar wind. However, the complicated nature of the Schumann resonances, dependent on multiple variables and subject to multiple unavoidable interferences (e.g., lightning or human radio sources), in conjunction with the complex magnetosphere‐ionosphere‐atmosphere coupling processes, makes it difficult to conclude that the observed deviations are exclusively due to the solar events mentioned. Results extracted from only two solar events cannot be considered as conclusive, and therefore, independent comparison with results reported by other research would seem advisable in future works on this subject.

Solar Cycle-Modulated Deformation of the Earth–Ionosphere Cavity

“…Solar X-ray bursts (Roldugin et al, 2004b;Sátori et al, 2005;Dyrda et al, 2015;Sátori et al, 2016;Shvets et al, 2017) and solar proton events (Schlegel and Füllekrug, 1999;Roldugin et al, 2003;Singh et al, 2014) are known to cause such changes in frequencies (of both signs). In contrast, occasional variations in SR intensity with extra-terrestrial origin have been associated only with solar proton events so far (Schlegel and Füllekrug, 1999;Roldugin et al, 2003), and recently, indication for periods with increased SR intensity during geomagnetic storms was demonstrated as well (Salinas et al, 2016;Pazos et al, 2019). We note that variations in SR were also reported connected to seismic activity (e.g., Christofilakis et al, 2019;Galuk et al, 2019;Florios et al, 2020;Hayakawa et al, 2020).…”

Geospace system responses to the St. Patrick's Day storms in 2013 and 2015

“…Their study suggested the importance of the inductive electric field and also confirmed that the largest proton losses are indeed at the minimum Dst and the losses are pitch angle dependent. Examining the connection between solar events and extremely low frequency electromagnetic waves in the atmosphere, Salinas et al [] found significant changes in the Schumann resonances in peak amplitudes and frequencies during both storm events in 2013 and 2015. High‐latitude responses. The energy inputs to the high‐latitude regions created significant ionospheric disturbances during the two storms.…”

A new portable ELF Schumann resonance receiver: design and detailed analysis of the antenna and the analog front-end

“…Due to the fact that our core is a rod that is open-ended, the resultant equivalent magnetic permeability is much smaller than the mumetal relative magnetic permeability and is given by Eqs. (1) and (2). Also, it strongly depends on the relative permeability of the core material as well as on the induction coil geometry through demagnetization factor N. Equations (1) and (2) give demagnetization factor N and the resultant magnetic permeability (μ) of an induction coil.…”

“…The Schumann resonances (SR) are electromagnetic oscillations of the Earth-ionosphere cavity at frequencies of 7.8, 14, 20, 26, 33, 39, and 45 Hz. The long-term monitoring of the Schumann phenomenon has recently drawn attention, not least from the space-geophysics community [1][2][3]. SR measurements and analysis provide information on the planetary thunderstorm activities, the properties of lower ionosphere layers, the Earth surface and atmosphere temperature variations, and the properties of earthquakes as well as on the studies of other celestial bodies [4][5][6][7][8][9].…”