Auroral omega bands are a significant cause of large geomagnetically induced currents

Apatenkov, S.; Pilipenko, Vyacheslav; Gordeev, E.; Viljanen, A.; Juusola, Liisa; Belakhovsky, V. B.; Sakharov, Ya. A.; Селиванов, В. Н.

doi:10.5194/egusphere-egu2020-19755

Cited by 17 publications

(36 citation statements)

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“…The field of view of the auroral imager moved successively farther west with each successive orbit because of Earth's rotation relative to a fixed orbital plane. As was the case for the event studied by Apatenkov et al (2020), these images show that omega bands along the morning sector auroral oval were evident both before and during the 05–08 UT interval of MPEs shown in Figures 11 and 12.…”

Section: Discussionsupporting

confidence: 78%

“…In contrast, within the postmidnight interval sharp pulses were seen at different times at each site over a span of ~1.5 hr. Their multiple rapid variations resembled those of Pi 3 or Ps 6 pulsations (Apatenkov et al, 2020; Opgenoorth et al, 1983; Solovyev et al, 1999) rather than solitary impulses.…”

Section: Event Studiesmentioning

confidence: 81%

“…A recent paper by Apatenkov et al (2020) also provided detailed observations of a very large GIC that was associated with an interval of omega bands. They modeled this event using the sum of two basic current systems: a 1‐D linear current (mimicking the auroral electrojet) and a 2‐D vortex that passed eastward over the field of view of the ground magnetometers.…”

Section: Discussionmentioning

confidence: 99%

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Interhemispheric Comparisons of Large Nighttime Magnetic Perturbation Events Relevant to GICs

et al. 2020

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Nearly all studies of impulsive magnetic perturbation events (MPEs) with large magnetic field variability (dB/dt) that can produce dangerous geomagnetically induced currents (GICs) have used data from the Northern Hemisphere. Here we present details of four large‐amplitude MPE events (|ΔBx| > 900 nT and |dB/dt| > 10 nT/s in at least one component) observed between 2015 and 2018 in conjugate high‐latitude regions (65–80° corrected geomagnetic latitude), using magnetometer data from (1) Pangnirtung and Iqaluit in eastern Arctic Canada and the magnetically conjugate South Pole Station in Antarctica and (2) the Greenland West Coast Chain and two magnetically conjugate chains in Antarctica, AAL‐PIP and BAS LPM. From one to three different isolated MPEs localized in corrected geomagnetic latitude were observed during three premidnight events; many were simultaneous within 3 min in both hemispheres. Their conjugate latitudinal amplitude profiles, however, matched qualitatively at best. During an extended postmidnight interval, which we associate with an interval of omega bands, multiple highly localized MPEs occurred independently in time at each station in both hemispheres. These nighttime MPEs occurred under a wide range of geomagnetic conditions, but common to each was a negative interplanetary magnetic field Bz that exhibited at least a modest increase at or near the time of the event. A comparison of perturbation amplitudes to modeled ionospheric conductances in conjugate hemispheres clearly favored a current generator model over a voltage generator model for three of the four events; neither model provided a good fit for the premidnight event that occurred near vernal equinox.

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Section: Discussionsupporting

confidence: 78%

Section: Event Studiesmentioning

confidence: 81%

Section: Discussionmentioning

confidence: 99%

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Interhemispheric Comparisons of Large Nighttime Magnetic Perturbation Events Relevant to GICs

et al. 2020

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“…2006; Weigel et al., 2003). In addition to these, auroral omega bands are another phenomenon which can be responsible for large d B /d t and GIC events (Apatenkov et al., 2020).…”

Section: Introductionmentioning

confidence: 99%

On the Regional Variability of dB/dt and Its Significance to GIC

et al. 2020

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Faraday's law of induction is responsible for setting up a geoelectric field due to the variations in the geomagnetic field caused by ionospheric currents. This drives geomagnetically induced currents (GICs) which flow in large ground‐based technological infrastructure such as high‐voltage power lines. The geoelectric field is often a localized phenomenon exhibiting significant variations over spatial scales of only hundreds of kilometers. This is due to the complex spatiotemporal behavior of electrical currents flowing in the ionosphere and/or large gradients in the ground conductivity due to highly structured local geological properties. Over some regions, and during large storms, both of these effects become significant. In this study, we quantify the regional variability of dB/dt using closely placed IMAGE stations in northern Fennoscandia. The dependency between regional variability, solar wind conditions, and geomagnetic indices are also investigated. Finally, we assess the significance of spatial geomagnetic variations to modeling GICs across a transmission line. Key results from this study are as follows: (1) Regional geomagnetic disturbances are important in modeling GIC during strong storms; (2) dB/dt can vary by several times up to a factor of three compared to the spatial average; (3) dB/dt and its regional variation is coupled to the energy deposited into the magnetosphere; and (4) regional variability can be more accurately captured and predicted from a local index as opposed to a global one. These results demonstrate the need for denser magnetometer networks at high latitudes where transmission lines extending hundreds of kilometers are present.

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“…Though the power of such processes is much lower than the power of magnetospheric storms and substorms, the rapidly varying electromagnetic fields of these disturbances can induce a significant GIC (Apatenkov et al, 2004;Belakhovsky et al, 2018;Viljanen, 1998). The events were presented when the ULF variations of the Pi3 or Ps6 type induced GIC in power transmission line up to 120 A (Apatenkov et al, 2020;Belakhovsky et al, 2019). Viljanen et al (2001) suggested that the Pc5 waves during the recovery phase of a magnetic storm may cause intense GICs.…”

Section: Introductionmentioning

confidence: 99%

Spatial scale of geomagnetic Pc5/Pi3 pulsations as a factor of their efficiency in generation of geomagnetically induced currents

Yagova

Pilipenko²,

Sakharov³

et al. 2020

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Geomagnetically induced currents (GICs) in a meridional power transmission line on the Kola Peninsula are analyzed during the intervals of Pc5/Pi3 (frequency range from 1.5 to 5 mHz) pulsations recorded at the IMAGE magnetometer network. We have analyzed GIC in a transformer at the terminal station Vykhodnoj (68 N, 33 E) during the entire year of 2015, near the maximum of 24-th Solar cycle. To quantify the efficiency of GIC generation by geomagnetic pulsations, a ratio between power spectral densities of GIC and magnetic field variations is introduced. Upon examination of the geomagnetic pulsation efficiency in GIC generation, the emphasis is given to its dependence on frequency and spatial scale. To estimate pulsation spatial scales in latitudinal and longitudinal directions, the triangle of stations KEV-SOD-KIL has been used. Large-scale pulsations (with a high spectral coherence, low phase difference, and similar amplitudes at latitudinally separated stations) are found to be more effective in GIC generation than small-scale pulsations. The GIC response also depends on the pulsation scale across the electric power line.

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Auroral omega bands are a significant cause of large geomagnetically induced currents

Cited by 17 publications

References 0 publications

Interhemispheric Comparisons of Large Nighttime Magnetic Perturbation Events Relevant to GICs

Interhemispheric Comparisons of Large Nighttime Magnetic Perturbation Events Relevant to GICs

On the Regional Variability of dB/dt and Its Significance to GIC

Spatial scale of geomagnetic Pc5/Pi3 pulsations as a factor of their efficiency in generation of geomagnetically induced currents

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