The AUTUMNX magnetometer meridian chain in Québec, Canada

Connors, Martin; Schofield, Ian; Reiter, Kyle; J., P.; Rowe, K.; Russell, C. T.

doi:10.1186/s40623-015-0354-4

Cited by 29 publications

(35 citation statements)

References 42 publications

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“…The left plot of Figure 1 and the Athabasca University THEMIS UCLA Magnetometer Network (Connors et al, 2016). All of three curves show a clear negative bay-like variation with decreasing AL that of ATHA starting at~09:54 UT (marked by the vertical solid line in the figure) was followed by those of the other two, indicating that substorm expansion began near ATHA and then expanded both westward and eastward toward WHIT and TPAS.…”

Section: Resultsmentioning

confidence: 62%

Substorm‐Associated Ionospheric Flow Fluctuations During the 27 March 2017 Magnetic Storm: SuperDARN‐Arase Conjunction

Hori

Нишитани

Shepherd

et al. 2018

Geophysical Research Letters

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Super Dual Auroral Radar Network (SuperDARN) observations show that ionospheric flow fluctuations of millihertz or lower-frequency range with horizontal velocities of a few hundred meters per second appeared in the subauroral to midlatitude region during a magnetic storm on 27 March 2017. A set of the radars have provided the first ever observations that the fluctuations propagate azimuthally both westward and eastward simultaneously, showing bifurcated phase propagation associated with substorm expansion. Concurrent observations near the conjugate site in the inner magnetosphere made by the Arase satellite provide evidence that multiple drifting clouds of electrons in the near-Earth equatorial plane were associated with the electric field fluctuations propagating eastward in the ionosphere. We interpret this event in terms of mesoscale pressure gradients carried by drifting ring current electrons that distort field lines one after another as they drift through the inner magnetosphere, causing eastward propagating ionospheric electric field fluctuations. Plain Language SummaryMidlatitude ionospheric radars called SuperDARN observed azimuthally propagating fluctuations of ionospheric plasma flow in association with substorm expansion during a magnetic storm on 27 March 2017. The radar observations have shown for the first time that the flow fluctuations bifurcate toward eastward and westward simultaneously. The Arase satellite in the near-conjugate site of the eastward propagating ionospheric flow fluctuations in the inner magnetosphere saw repeated flux enhancement of energetic electrons. The good satellite-radar conjunction gives observational evidence that the eastward propagating ionospheric flow fluctuations are driven by eastward drifting pressure bumps of electrons injected into the inner magnetosphere upon substorm expansion.

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Section: Resultsmentioning

confidence: 62%

Substorm‐Associated Ionospheric Flow Fluctuations During the 27 March 2017 Magnetic Storm: SuperDARN‐Arase Conjunction

Hori

Нишитани

Shepherd

et al. 2018

Geophysical Research Letters

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“…We use the mapping technique of Ozeke et al () to obtain equatorial quasi‐azimuthal electric field E ϕ from the magnetic east‐west D‐component of magnetic field on the ground. We use measurements of the magnetic field obtained by the CARISMA magnetometer array (Mann et al, ) and AUTUMN magnetometer array (Connors et al, ). In particular, we use the magnetometer data from Fort Smith ( L =6.69) to obtain E ϕ near GOES‐13, and the magnetometer data from Inukjuak ( L = 6.91) to obtain E ϕ near GOES‐15.…”

Section: Methodsmentioning

confidence: 99%

On the Relative Strength of Electric and Magnetic ULF Wave Radial Diffusion During the March 2015 Geomagnetic Storm

et al. 2019

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In this paper, we study electron radial diffusion coefficients derived from Pc4-Pc5 ultralow frequency (ULF) wave power during the intense geomagnetic storm on 17-18 March 2015. During this storm the population of highly relativistic electrons was depleted within 2 hr of the storm commencement. This radial diffusion, depending upon the availability of source populations, can cause outward radial diffusion of particles and their loss to the magnetosheath, or inward transport and acceleration. Analysis of electromagnetic field measurements from Geostationary Operational Environment Satellite (GOES), Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellite, and ground-based magnetometers shows that the main phase storm-specific radial diffusion coefficients do not correspond to statistical estimates. Specifically, during the main phase, the electric diffusion (D E LL ) is reduced, and the magnetic diffusion (D B LL ) is increased, compared to empirical models based on Kp. Contrary to prior results, the main phase magnetic radial diffusion cannot be neglected. The largest discrepancies, and periods of dominance of D B LL over D E LL , occur during intervals of strongly southward IMF. However, during storm recovery, both magnetic and electric diffusion rates are consistent with empirical estimates. We further verify observationally, for the first time, an energy coherence for both D B LL and D E LL where diffusion coefficients do not depend on energy. We show that, at least for this storm, properly characterizing main phase radial diffusion, potentially associated with enhanced ULF wave magnetopause shadowing losses, cannot be done with standard empirical models. Modifications, associated especially with southward IMF, which enhance the effects of D B LL and introduce larger main phase outward transport losses, are needed.Recent long-term radiation belt simulations by Drozdov et al. (2017) suggest that EMIC wave losses, parametrized in their model using solar wind dynamic pressure, may be important. However, recent studies,

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“…Magnetometer data used in this study were recorded by four arrays in Arctic Canada: MACCS (Engebretson et al, 1995), AUTUMNX (Connors et al, 2016), CANMOS (Nikitina et al, 2016), and CARISMA (Mann et al, 2008), as well as the Greenland Coastal array (http://www.space.dtu.dk/English/Research/ Scientific_data_and_models/Magnetic_Ground_Stations.aspx), the conjugate AAL-PIP array in Antarctica (Clauer et al, 2014), and the fluxgate magnetometer at South Pole Station, Antarctica (Engebretson et al, 1997). Auroral images were obtained by the THEMIS all-sky white light imagers (Mende et al, 2008).…”

Section: Instrumentationmentioning

confidence: 99%

Nighttime Magnetic Perturbation Events Observed in Arctic Canada: 2. Multiple‐Instrument Observations

et al. 2019

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The rapid changes of magnetic fields associated with nighttime magnetic perturbations with amplitudes |ΔB| of hundreds of nanoteslas and 5‐ to 10‐min periods can induce bursts of geomagnetically induced currents that can harm technological systems. This paper presents three cases of intervals of intense and complex nighttime magnetic perturbations in eastern Arctic Canada in 2015, augmented by observations from auroral imagers and high‐altitude spacecraft in the nightside magnetosphere. Each case occurred within 1 hr after substorm onsets. None occurred during the main phase of a geomagnetic storm, and only the first during the early recovery phase (of a moderate storm). The cases were similar in that two or three intervals occurred in this region over a span of ~1 hr; these showed a spatial progression, in that successive intervals occurred later at more western and northern stations. During several intervals, individual peak Bx impulses occurred nearly simultaneously (within 1–2 min) at several stations, while during others the impulses occurred later at more western and northern stations, and during one interval they occurred later at southern stations. During both of the cases for which auroral images were available, a westward traveling surge and a poleward auroral expansion and/or poleward boundary intensification occurred, and during two events auroral streamers coincided in time and location with magnetic perturbations. These observations appear to be consistent with several earlier studies connecting nighttime magnetic perturbation events to localized auroral structures and to dipolarizing flux bundles and bursty bulk flows in the magnetotail.

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The AUTUMNX magnetometer meridian chain in Québec, Canada

Cited by 29 publications

References 42 publications

Substorm‐Associated Ionospheric Flow Fluctuations During the 27 March 2017 Magnetic Storm: SuperDARN‐Arase Conjunction

Substorm‐Associated Ionospheric Flow Fluctuations During the 27 March 2017 Magnetic Storm: SuperDARN‐Arase Conjunction

On the Relative Strength of Electric and Magnetic ULF Wave Radial Diffusion During the March 2015 Geomagnetic Storm

Nighttime Magnetic Perturbation Events Observed in Arctic Canada: 2. Multiple‐Instrument Observations

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