The equatorial electrojet (EEJ) current deduced from CHAMP satellite and ground magnetic measurements in West Africa

Benaissa, Mahfoud; Berguig, Mohamed Chérif; Doumbia, V.; Bouraoui, S.

doi:10.1007/s12517-017-3094-x

Cited by 2 publications

(2 citation statements)

References 34 publications

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“…The present study focuses on the distribution and variability of Sq currents in the mid‐latitudes. However, the EEJ effects, which correspond to the structure of the eastward sheet currents show a V‐shaped depression near the geomagnetic equator, are located within a latitude band of about±12° on either side of the geomagnetic equator (Benaissa et al., 2017; Maus et al., 2007). To ensure the stability of the fitting algorithm for a more accurate simulation of the Sq current system, the geomagnetic eastward current in the geomagnetic latitude range between 12°S and 12°N is substituted with the fitted value obtained from a polynomial function of degree 12 calculated based on the current data from the mid‐latitude region.…”

Section: Methodsmentioning

confidence: 99%

A Simulation Study of the Modulation of the Geomagnetic Field Configuration on the Seasonal Variation of Ionospheric Sq Currents

Liu,

Ren,

Wei

et al. 2024

JGR Space Physics

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Based on Global Coupled Ionosphere‐Thermosphere‐Electrodynamics Model, the solution of the 3‐dimensional current in the ionospheric region, the equivalent sheet current and filed‐aligned current are examined. The simulation study enables a comprehensive analysis of the effect of the geomagnetic field configuration, especially the non‐dipole component and tilt angle, on the ionospheric electrodynamics phenomena. Different geomagnetic field configurations are specified in the present work, including realistic geomagnetic field (RGF), tilted dipole geomagnetic field (TDGF) and zero‐declination dipole geomagnetic field (ZDGF). Our simulation focuses on the seasonal variation of Sq current, primarily governed by annual and semi‐annual variation. The modulation of the tilt angle of the geomagnetic field is globally distributed, whereas the modulation of the geomagnetic anomaly is localized. At mid‐latitudes, the annual mean and semi‐annual amplitudes of the Sq current are negatively correlated with the magnetic field strength, especially shown in geomagnetic anomaly area, while there is the opposite effect in the geomagnetic conjugate regions of the opposite hemispheres. The annual variation of Sq current system is more affected by the offset of the geomagnetic latitudes and geographical latitudes. The seasonal variation of the total Sq current is also modulated by the geomagnetic field. The annual mean, the annual and semi‐annual components of the total Sq current are negatively correlated with the magnetic field strength, while the annual variation is also controlled by the tilt angle of the geomagnetic field. The solar radiation affects the semi‐annual variation of the current more strongly than the annual variation.

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Section: Methodsmentioning

confidence: 99%

A Simulation Study of the Modulation of the Geomagnetic Field Configuration on the Seasonal Variation of Ionospheric Sq Currents

Liu,

Ren,

Wei

et al. 2024

JGR Space Physics

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“…The EEJ current can be calculated using the idea that a pair of magnetometers, with one located at the dip magnetic equator (± 2°) and, while the other (an offequatorial station) should be located ± 6°-9° away from the magnetic equator, with both stations in the same longitudes as suggested by Rastogi & Klobuchar (1990), Anderson et al (2004), Yamazaki & Maute (2017). Following Tomás et al (2008), Benaissa et al (2017), due to the unavailability of The computed coordinates presented here are based on the Geomagnetic Coordinates IGRF-13 revised in December 2019 using the epoch of 2013 (data from British Geological Survey 2019).…”

Section: Methodsmentioning

confidence: 99%

Solar Flux Effects on the Variations of Equatorial Electrojet (EEJ) and Counter-Electrojet (CEJ) Current across the Different Longitudinal Sectors during Low and High Solar Activity

Cherkos¹

2023

J. Astron. Space Sci.

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This study examined the effect of solar flux (F10.7) and sunspots number (R) on the daily variation of equatorial electrojet (EEJ) and morning/afternoon counter electrojet (MCEJ/ACEJ) in the ionospheric E region across the eight longitudinal sectors during quiet days from January 2008 to December 2013. In particular, we focus on both minimum and maximum solar cycle of 24. For this purpose, we have collected a 6-year ground-based magnetic data from multiple stations to investigate EEJ/CEJ climatology in the Peruvian, Brazilian, West & East African, Indian, Southeast Asian, Philippine, and Pacific sectors with the corresponding F10.7 and R data from satellites simultaneously. Our results reveal that the variations of monthly mean EEJ intensities were consistent with the variations of solar flux and sunspot number patterns of a cycle, further indicating that there is a significant seasonal and longitudinal dependence. During the high solar cycle period, F10.7 and R have shown a strong peak around equinoctial months, consequently, the strong daytime EEJs occurred in the Peruvian and Southeast Asian sectors followed by the Philippine regions throughout the years investigated. In those sectors, the correlation between the day Maxima EEJ and F10.7 strengths have a positive value during periods of high solar activity, and they have relatively higher values than the other sectors. A predominance of MCEJ occurrences is observed in the Brazilian (TTB), East African (AAE), and Peruvian (HUA) sectors. We have also observed the CEJ dependence on solar flux with an anti-correlation between ACEJ events and F10.7 are observed especially during a high solar cycle period.

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The equatorial electrojet (EEJ) current deduced from CHAMP satellite and ground magnetic measurements in West Africa

Cited by 2 publications

References 34 publications

A Simulation Study of the Modulation of the Geomagnetic Field Configuration on the Seasonal Variation of Ionospheric Sq Currents

A Simulation Study of the Modulation of the Geomagnetic Field Configuration on the Seasonal Variation of Ionospheric Sq Currents

Solar Flux Effects on the Variations of Equatorial Electrojet (EEJ) and Counter-Electrojet (CEJ) Current across the Different Longitudinal Sectors during Low and High Solar Activity

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