Distribution and Occurrence Frequency of dB/dt Spikes During Magnetic Storms 1980–2020

Schillings, Audrey; Palin, L.; Opgenoorth, H. J.; Hamrin, Maria; Rosenqvist, L.; Gjerloev, J. W.; Juusola, Liisa; Barnes, R. J.

doi:10.1029/2021sw002953

Cited by 24 publications

(71 citation statements)

References 67 publications

(146 reference statements)

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“…We first consider the results from 2016. In the case of all three magnetic components, spikes are observed near auroral latitudes of 64 to 74 • , concentrated in two main local time sectors, which we loosely refer to as pre-midnight (17 to 02 MLT) and dawn (02 to 09 MLT); these are the same "hotspots" identified by Schillings et al (2022) and previous workers. The boundaries of these MLT regions are indicated in the middle panel; we will refer to the 09 to 17 MLT sector as noon.…”

Section: Observations and Discussionsupporting

confidence: 53%

“…If we refer to a spike in any component, we use ∆B. Our method of analysis is similar to previous dB/dt studies using SuperMAG data (Rogers et al, 2020;Schillings et al, 2022).…”

Section: Observations and Discussionmentioning

confidence: 99%

“…They noted main peaks in occurrence associated with the pre-midnight, substorm region, the cusp, and subsolar region. Schillings et al (2022) performed a similar study and identified two main hotspots of spikes in the pre-midnight and dawn sectors during selected geomagnetic storms. In this study we also identify spikes in SuperMAG data, but perform a more longitudinal study over all levels of geomagnetic activity during solar cycles 23 and 24, years 1995 to 2020.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Solar cycle and solar wind dependence of the occurrence of large dB/dt events

Milan

Imber

Fleetham

et al. 2022

Preprint

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We investigate sharp changes in magnetic field that can produce Geomagnetically Induced Currents (GICs) which damage pipelines and power grids. We use one-minute cadence SuperMAG observations to find the occurrence distribution of magnetic field "spikes". Recent studies have determined recurrence statistics for extreme events and charted the local time distribution of spikes; however, their relation to solar activity and conditions in the solar wind is poorly understood. We study spike occurrence during solar cycles 23 and 24, roughly 1995 to 2020. We find three local time hotspots in occurrence: the pre-midnight region associated with substorm onsets, the dawn sector associated with omega band activity, and the pre-noon sector associated with the Kelvin-Helmholtz instability occurring at the magnetopause. Magnetic field perturbations are mainly North-South for substorms and KHI, and East-West for omega bands. Substorm spikes occur at all phases of the solar cycle, but maximise in the declining phase. Omega-band and KHI spikes are confined to solar maximum and the declining phase. Substorm spikes occur during moderate solar wind driving, omega band spikes during strong driving, and KHI spikes during quiet conditions but with high solar wind speed. We show that the shapes of these distributions do not depend on the magnitude of the spikes, so it appears that our results can be extrapolated to extreme events.

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Section: Observations and Discussionsupporting

confidence: 53%

“…If we refer to a spike in any component, we use ∆B. Our method of analysis is similar to previous dB/dt studies using SuperMAG data (Rogers et al, 2020;Schillings et al, 2022).…”

Section: Observations and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Solar cycle and solar wind dependence of the occurrence of large dB/dt events

Milan

Imber

Fleetham

et al. 2022

Preprint

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“…It transforms our traditional knowledge about the external source of ground magnetic field ULF oscillations, which considers geomagnetic ULF oscillations originally come from the solar wind or KHI along the flanks. Although several studies have shown that fewer geomagnetically induced currents are observed in the dayside than those observed in other MLTs (Engebretson et al., 2019; Schillings et al., 2022), magnetosheath HSJs are likely one important dayside driver of geomagnetically induced currents.…”

Section: Discussionmentioning

confidence: 90%

Investigating the Role of Magnetosheath High‐Speed Jets in Triggering Dayside Ground Magnetic Ultra‐Low Frequency Waves

Wang

Nishimura

Hietala

et al. 2022

Geophysical Research Letters

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“…We also highlight the interpretation of the time derivative of the radial magnetic field dB r /dt as the radial component of the curl of the geomagnetically induced electric field (Vanhamäki et al, 2013) and present a statistical analysis of the properties of this quantity. This analysis stands in contrast to the analysis of the time derivative of the horizontal magnetic field (often denoted ∂H/∂t), which has received comparatively much more attention (Juusola et al, 2020;Tanskanen et al, 2001;Viljanen et al, 2001;Schillings et al, 2022;Weigel et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Statistics of temporal variations in the auroralelectrojets over Fennoscandia

Walker

Laundal

Reistad

et al. 2022

Preprint

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We present the implementation of an improved technique to coherently model the high-latitude ionospheric equivalent current. By using a favourable and fixed selection of 20 ground magnetometers in Fennoscandia, we present a method based on Spherical Elementary Current Systems (SECS) to model the currents coherently during 2000-2020. Due to the north-south extent of the ground stations used, we focus on the model output along the 105 * magnetic meridian. In addition to the fixed data locations and SECS analysis grid, our improvements involve taking into account a priori knowledge of the large-scale current systems to improve the robustness of solving the underdetermined inverse problem. We account for contributions from ground induced currents assuming so-called mirror currents. An advantage of this data set over existing empirical models of ionospheric currents is the 1-min output resolution. High temporal resolution enables investigation of temporal changes in the magnetic field. We present an analysis of statistical properties of where (in magnetic latitude and local time) and at what rate ([?]Br /[?]t) the radial magnetic field component fluctuates. We show that [?]Br /[?]t, which is equivalent to the radial component of the curl of the induced electric field, is dependent on latitude, local time, and solar cycle. Other applications of the presented data set are also highlighted, including investigations of how Ultra Low Frequency oscillations in ground magnetic perturbations vary in space and time.

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Distribution and Occurrence Frequency of dB/dt Spikes During Magnetic Storms 1980–2020

Cited by 24 publications

References 67 publications

Solar cycle and solar wind dependence of the occurrence of large dB/dt events

Solar cycle and solar wind dependence of the occurrence of large dB/dt events

Investigating the Role of Magnetosheath High‐Speed Jets in Triggering Dayside Ground Magnetic Ultra‐Low Frequency Waves

Statistics of temporal variations in the auroralelectrojets over Fennoscandia

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