Estimation of global field aligned currents using the iridium® System magnetometer data

Waters, C. L.; Anderson, B. J.; Liou, K.

doi:10.1029/2000gl012725

Cited by 212 publications

(261 citation statements)

References 19 publications

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“…Additionally there are localised conductance enhancements due to particle precipitation (Hardy et al, 1987), mostly from auroral particle acceleration. Upward FACs identified using Iridium data were shown to be colocated with far ultra-violet auroral emissions, particularly R1 on the duskside (Waters et al, 2001). …”

Section: Summary Of Seasonal Fac Observationsmentioning

confidence: 99%

“…Data accumulated over a one hour period is usually required to provide sufficient data to the fitting algorithm. A more representative pattern is obtained when the FACs show little to no variation over the one hour interval (see Anderson et al, 2000;Waters et al, 2001). We have processed all available Iridium data from September 1999 through to December 2006 and selected intervals where the current patterns are stable.…”

Section: Event Selectionmentioning

confidence: 99%

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Seasonal and interplanetary magnetic field dependence of the field-aligned currents for both Northern and Southern Hemispheres

et al. 2009

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Abstract. The configuration of the Earth's magnetosphere under various Interplanetary Magnetic Field (IMF) and solar wind conditions alters the global distribution of FieldAligned Currents (FACs) at the high latitude ionospheres. We use magnetic field data obtained from the Iridium constellation to extend recent studies that infer the dependence of the global FAC configuration on IMF direction and magnitude, hemisphere and season. New results are a reduced IMF B y influence on the FAC configuration for the winter hemisphere and a redistribution of FAC to the nightside for winter relative to the summer hemisphere. These effects are linked to the winter ionosphere conductance distribution being dominated by localised nightside enhancement associated with ionisation from energetic particle precipitation. A comparison of an estimated open-closed field line boundary (OCFLB) with the Region 1 FAC locations shows reasonable agreement for summer FAC configurations. However, the OCFLB location is decoupled from the Region 1 FACs in winter, especially for IMF B z >0.

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Section: Summary Of Seasonal Fac Observationsmentioning

confidence: 99%

Section: Event Selectionmentioning

confidence: 99%

Seasonal and interplanetary magnetic field dependence of the field-aligned currents for both Northern and Southern Hemispheres

et al. 2009

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“…The Active Magnetosphere and Planetary Electrodynamics Experiment (AMPERE) infers maps of field-aligned current density in the northern and southern polar regions at a 10 min cadence, fitting a spherical harmonic expansion to the horizontal magnetic perturbations measured by the 66 spacecraft of the Iridium® telecommunications constellation (Anderson et al 2000(Anderson et al , 2002Waters et al 2001;Green et al 2006). The spacecraft are arranged in six polar orbital planes uniformly spaced in local time, eleven spacecraft to each orbit at an altitude of 780 km.…”

Section: Datasetsmentioning

confidence: 99%

Overview of Solar Wind–Magnetosphere–Ionosphere–Atmosphere Coupling and the Generation of Magnetospheric Currents

et al. 2017

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We review the morphology and dynamics of the electrical current systems of the terrestrial magnetosphere and ionosphere. Observations from the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) over the three years 2010 to 2012 are employed to illustrate the variability of the field-aligned currents that couple the magnetosphere and ionosphere, on timescales from minutes to years, in response to the impact of solar wind disturbances on the magnetosphere and changes in the level of solar illumination of the polar ionospheres. The variability is discussed within the context of the occurrence of magnetic reconnection between the solar wind and terrestrial magnetic fields at the magnetopause, the transport of magnetic flux within the magnetosphere, and the onset of magnetic reconnection in the magnetotail. The conditions under which the currents are expected to be weak, and hence minimally contaminate measurements of the internallyproduced magnetic field of the Earth, are briefly outlined.

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“…Each satellite is equipped with a 30-nT resolution engineering magnetometer, which can be used to detect magnetic perturbations due to Birkeland currents. These data are routinely used to derive global maps of Birkeland currents (Anderson et al, 2000;Waters et al, 2001). An intermediate product in the derivation of the currents is the distribution of the horizontal vector magnetic perturbations, b, due to the Birkeland currents and is associated with the poloidal ionospheric current (Waters et al, 2001).…”

Section: Iridium Datamentioning

confidence: 99%

High-latitude electromagnetic and particle energy flux during an event with sustained strongly northward IMF

et al. 2005

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Abstract. We present a case study of a prolonged interval of strongly northward orientation of the interplanetary magnetic field on 16 July 2000, 16:00-19:00 UT to characterize the energy exchange between the magnetosphere and ionosphere for conditions associated with minimum solar windmagnetosphere coupling. With reconnection occurring tailward of the cusp under northward IMF conditions, the reconnection dynamo should be separated from the viscous dynamo, presumably driven by the Kelvin-Helmholtz (KH) instability. Thus, these conditions are also ideal for evaluating the contribution of a viscous interaction to the coupling process. We derive the two-dimensional distribution of the Poynting vector radial component in the northern sunlit polar ionosphere from magnetic field observations by the constellation of Iridium satellites together with drift meter and magnetometer observations from the Defense Meteorological Satellite Program (DMSP) F13 and F15 satellites. The electromagnetic energy flux is then compared with the particle energy flux obtained from auroral images taken by the far-ultraviolet (FUV) instrument on the Imager for Magnetopause to Aurora Global Exploration (IMAGE) spacecraft. The electromagnetic energy input to the ionosphere of 51 GW calculated from the Iridium/DMSP observations is eight times larger than the 6 GW due to particle precipitation all poleward of 78 • MLAT. This result indicates that the energy transport is significant, particularly as it is concentrated in a small region near the magnetic pole, even under conditions traditionally considered to be quiet and is dominated by the electromagnetic flux. We estimate the contributions of the high and mid-latitude dynamos to both the Birkeland currents and electric potentials finding that highlatitude reconnection accounts for 0.8 MA and 45 kV while we attribute <0.2 MA and ∼5 kV to an interaction at lower latitudes having the sense of a viscous interaction. Given that these conditions are ideal for the occurrence of the KH instability at the magnetopause and hence the viscous interaction, Correspondence to: H. Korth (haje.korth@jhuapl.edu) this result suggests that the viscous interaction is a small contributor to coupling solar wind energy to the magnetosphereionosphere system.

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Estimation of global field aligned currents using the iridium® System magnetometer data

Cited by 212 publications

References 19 publications

Seasonal and interplanetary magnetic field dependence of the field-aligned currents for both Northern and Southern Hemispheres

Seasonal and interplanetary magnetic field dependence of the field-aligned currents for both Northern and Southern Hemispheres

Overview of Solar Wind–Magnetosphere–Ionosphere–Atmosphere Coupling and the Generation of Magnetospheric Currents

High-latitude electromagnetic and particle energy flux during an event with sustained strongly northward IMF

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