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Ionospheric perturbations: a case study of 2007 five major earthquakes using DEMETER data

Thomas Jewel Emem, Ekanem Aniekan Martin, George Nyakno Jimmy, Akpan Anthony Effiong

Acta Geophysica

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2023

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Vol. 71, no. 4

1607--1618

EN

Using the Plasma analyzer (IAP) and Langmuir Probe (ISL) experiments of the Detection of Electromagnetic Emissions Transmitted from Earthquake Regions (DEMETER) lithospheric–atmospheric–ionospheric coupling has been observed before, during and after five major earthquakes with magnitudes greater than 6.5. The aim of this study is to use ionospheric parameters to identify the ionospheric perturbations associated with the five earthquake regions screened. All the three investigated ionospheric parameters of electron density, electron temperature and total ion density recorded perturbations within the investigative period. A total of 36 anomalies were obtained with 18 each for nighttime and daytime readings. The observed anomalies being screened for false alarm using the geomagnetic indices of Kernnifzer digit (kp) and disturbance storm time (Dst.) revealed 27.8% as geomagnetically induced perturbations. Thus, 72.2% of the studied anomalies transpired in quiet geomagnetic conditions, which is linked to seismic events.

2

Study of the lightning activity over Poland for different solar activity

Błęcki Jan, Iwański Rafał, Wronowski Roman, Jujeczko Paweł

Artificial Satellites : Journal of Planetary Geodesy

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2022

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Vol. 57, No. 4

194--209

EN

The question of the connection between solar and thunderstorm activity is not new. The discussion among scientists began before the cosmic era. The correlations of the ground-based registration of the cosmic ray flux and meteorological observations have been performed since the 50s of the 20th century. The discussed problem is related to the influence of cosmic rays on the creation of clouds, particularly thunderstorm clouds. The intensity of the galactic cosmic ray flux is controlled by the density and velocity of the solar wind. The increase in the solar wind flux during high solar activity leads to decreasing galactic cosmic ray flux, but on the other hand, the solar activity creates solar cosmic rays. Using data from the PERUN system and the DEMETER satellite, we tried to estimate the connection between the thunderstorm activity in Poland and solar activity during the period of the DEMETER operational activity (2004-2010). The influence of thunderstorms on the ionosphere and its dependence on solar activity is also discussed. However, due to the short time interval of the available data covering an insignificant part of the solar cycle, close to the minimum activity, our findings are not fully conclusive. No correlation was found between the cosmic ray flux and lightning activity given by the number of the discharges. However, some of the most energetic lightning discharges in the analyzed period occurred close to the minimum of the solar activity and their appearance is discussed.

3

Comparative study of the energetic electrons registered together with the broad band emissions in different regions of the ionosphere

Błęcki Jan, Wronowski Roman, Słomiński Jan, Savin Sergey, Iwański Rafał, Haagmans Roger

Artificial Satellites : Journal of Planetary Geodesy

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2020

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Vol. 55, No. 4

130--149

EN

ELF/VLF waves have been registered in the outer polar cusps simultaneously with high energy electrons fluxes by the satellites Magion 4 (subsatellite to Interball 1), Polar and CLUSTER. Further, we discuss similar observations in the different regions of the ionosphere, where DEMETER registered energetic electrons. The DEMETER satellite operating on the nearly polar orbit at the altitude 650 km crossed different regions in the ionosphere. Registrations of ELF/VLF/HF waves together with the energetic electrons in the polar cusp, in the ionospheric trough and over thunderstorm areas are presented in this paper. The three satellites of ESA’s Swarm mission provide additional information on the ELF waves in the mentioned areas together with electron density and temperature. A brief discussion of the generation of these emissions by the so-called “fan instability” (FI) and beam instability is presented.

4

Impact of induced field on the estimation of the ionospheric electric field

Makhlouf S., Djebli M.

Acta Geophysica

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2019

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Vol. 67, no. 6

1671--1677

EN

The ionospheric plasma electric field plays an important role in space physics and space meteorology, and it constitutes an essential physics magnitude for all phenomena occurring in the ionosphere, such as plasma convection, wave–particle interactions, and wave emissions. We used the direct measurements of DEMETER satellite which gives the total electric field, i.e., natural and induced fields, to show the effect of the induced field on the total electric field measurements. For that purpose, the induced electric field, generated by the satellite motion through the Earth’s magnetic lines, is calculated by selecting different velocity satellite and geomagnetic field components. The induced field is calculated by using two different methods: one according to the satellite different axes and the other by using the double-probe method. It is found that the calculated induced electric field dominates on the total electric measurements, therefore leadings to misestimation of the true value of ionospheric electric field.

5

Seasonal Variations of Mid-Latitude Ionospheric Trough Structure Observed with DEMETER and COSMIC

Matyjasiak B., Przepiórka D., Rothkaehl H.

Acta Geophysica

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2016

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Vol. 64, no. 6

2734--2747

EN

The mid-latitude ionospheric trough is a depleted region of ionospheric plasma observed in the topside ionosphere. Its behavior can provide useful information about the magnetospheric dynamics, since its existence is sensitive to magnetospherically induced motions. Midlatitude trough is mainly a night-time phenomenon. Both, its general features and detailed characteristics strongly depend on the level of geomagnetic disturbances, time of the day, season, and the solar cycle, among others. Although many studies provide basic information about general characteristics of the main ionospheric trough structure, an accurate prediction of the trough behavior in specific events is still understood poorly. The paper presents the mid-latitude trough characteristics with regard to the geomagnetic longitude and season during a solar activity minimum, as based on the DEMETER in situ satellite measurements and the data retrieved from FORMOSAT-3/COSMIC radio occultation measurements.