Modelling of geomagnetically induced currents during geomagnetic storms using geoelectric fields and auroral electrojet indices

Falayi, E.O.; Beloff, Natalia

doi:10.1007/s12648-012-0108-0

Cited by 14 publications

(6 citation statements)

References 21 publications

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“…The amplitudes evaluated for both the MPs of the September 2017 GS are comparable with the results obtained by Pulkkinen et al (), Viljanen et al (), Falayi and Beloff (), Pulkkinen et al (), and Marshall et al ().…”

Section: Magnetospheric and Ionospheric Contribution To Gicsupporting

confidence: 89%

“…model at low latitudes, in general, shows amplitudes smaller than at high latitudes, confirming the dominant character of the ionospheric origin field with respect to the magnetospheric one. In addition, we showed how the amplitude of

{\overset{E}{true}}_{GIC}

during the SI is ∼30% smaller than during the MP (Falayi & Beloff, ; Pulkkinen et al, ). The decomposition of

{\overset{E}{true}}_{GIC}

gives the possibility to quantify for the first time the magnetospheric and the ionospheric origin contribution causing the geoelectric field and hence GIC.…”

Section: Discussionmentioning

confidence: 58%

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Geoelectric Field Evaluation During the September 2017 Geomagnetic Storm: MA.I.GIC. Model

et al. 2019

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Section: Magnetospheric and Ionospheric Contribution To Gicsupporting

confidence: 89%

{\overset{E}{true}}_{GIC}

during the SI is ∼30% smaller than during the MP (Falayi & Beloff, ; Pulkkinen et al, ). The decomposition of

{\overset{E}{true}}_{GIC}

gives the possibility to quantify for the first time the magnetospheric and the ionospheric origin contribution causing the geoelectric field and hence GIC.…”

Section: Discussionmentioning

confidence: 58%

Geoelectric Field Evaluation During the September 2017 Geomagnetic Storm: MA.I.GIC. Model

et al. 2019

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“…To solve this issue, the contributions due to the GICs are eliminated from the hourly D component of the geomagnetic field according to the following equation

normalΔ D = D_{local} - {GIC}_{H}

where D local is the observed D component of the geomagnetic field perturbations at any particular hour and GIC H is the estimated value of the effect of magnetic field variations that are associated with GICs for the same particular hour. The GIC H estimates are calculated as the summation of the north and east directed electric field using the technique by Viljanen () and Falayi and Beloff (). This technique is based on the fact that the time derivative of the horizontal magnetic field, the horizontal surface geoelectric field, and GIC activity are closely related (Pulkkinen et al, ; Viljanen, ; Viljanen et al, ).…”

Section: Methodsmentioning

confidence: 99%

Excursions of Interhemispheric Field‐Aligned Currents in Africa

et al. 2018

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The interhemispheric field‐aligned currents (IHFACs) are the most evident currents connecting the solar quiet (Sq) current systems in the Northern and Southern Hemispheres. Understanding these coupling currents has practical importance for space weather forecast of the magnetosphere‐ionosphere interactions and their potential impacts on low‐orbiting spacecraft. In this paper, we have examined digital magnetic records from September 2008 to August 2009 at nine Magnetic Data Acquisition System (MAGDAS) stations in order to uniquely determine the variability of IHFACs in terms of their excursions in the African sector. By excursions, we mean the direction in which the IHFACs are moving as a function of local time or latitude. Different from theoretical prediction, we found prominent positive IHFACs around dusk in February and March equinox. A novel feature of this study is the semidiurnal variation control of the coupling between the Northern and Southern Hemispheres. In addition, we found terdiurnal variation in September with their associated strong diurnal variations from October through December. Quite unexpectedly, in January, a significant latitudinal depletion in the intensities of IHFACs was observed from dawn to dusk, compared to any other months under investigation, accompanied with a marked reduction of the prominent diurnal variations at the magnetic equator (Addis Ababa, AAB). The fact that the excursions of IHFACs in January experience an unusual retardation with respect to their intensities points to a relation with the effects of sudden stratospheric warming.

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“…Large GICs are usually observed at high latitudes in or near the auroral regions where strong auroral electrojet currents that are one of the principal causes of the geomagnetic disturbances leading to GICs occur. (Pirjola, 2005;Wik et al, 2009;Eroshenko et al, 2010;Falayi and Beloff, 2012;Stauning, 2013;Myllys et al, 2014). It was believed that mid-and low-latitude regions are not affected by GICs.…”

Section: Introductionmentioning

confidence: 99%

The Use of Horizontal Geomagnetic Field Components for Estimation of Geomagnetically Induced Current Over Turkey During Space Weather Events

Timoçin

Erat

2020

Turkish Journal of Engineering

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In this study, the time derivatives of the horizontal geomagnetic field components were computed to estimate the geomagnetically induced current (GIC) over Turkey during space weather events and the results were compared with the geomagnetic activity indices. The interplanetary magnetic field (IMF) index, disturbance storm time (Dst) index, global geomagnetic activity indices (ap and Kp) were used as indicator of space weather events. The changes because of solar flares and coronal mass ejections in the space environment between the Sun and Earth are defined as space weather events. Such events' effects on the Earth's magnetosphere are called geomagnetic storms. In this study, two different space weather events that occurred on 20-26 June 2015 and 06-10 September 2017 are analyzed. The data of the horizontal magnetic field components used in the analysis are obtained from İznik magnetic observatory (40.5 ⸰ N, 29.7 ⸰ E). During space weather event on 20-26 June 2015, the maximum (max.) value of time derivative of (dX/dt and dH/dt) X and H horizontal magnetic field components were calculated as 72,22 nT/min. and 74,40 nT/min., respectively, while during space weather event on 06-10 September 2017, the max. value of the time derivative of the X and H horizontal magnetic field components are calculated and the results are 36,90 nT/min. and 38,12 nT/min., respectively. Also, it was observed that the strength of the local geomagnetic disturbance and amplitude of dX/dt and dH/dt at the observatory station depend strongly on the characteristics of geomagnetic activity indices during the space weather events. The southward IMF Bz component induces larger amplitude of dX/dt and dH/dt. The results indicate that the possibility of GIC occurrence over Turkey is quite high. Therefore, we strongly believe that further research and experiment on GIC for Turkey is important.

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Modelling of geomagnetically induced currents during geomagnetic storms using geoelectric fields and auroral electrojet indices

Cited by 14 publications

References 21 publications

Geoelectric Field Evaluation During the September 2017 Geomagnetic Storm: MA.I.GIC. Model

Geoelectric Field Evaluation During the September 2017 Geomagnetic Storm: MA.I.GIC. Model

Excursions of Interhemispheric Field‐Aligned Currents in Africa

The Use of Horizontal Geomagnetic Field Components for Estimation of Geomagnetically Induced Current Over Turkey During Space Weather Events

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