The Image Observatory

Gibson, William C.; Burch, J. L.; Scherrer, J.; Tapley, Mark B.; Killough, Ronnie; Volpe, F. A.; Davis, W. D.; Vaccarello, D. C.; Grismore, G.; Sakkas, Dimitrios; Housten, S. J.

doi:10.1007/978-94-011-4233-5_2

Cited by 8 publications

(8 citation statements)

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“…The COmposition and DIstribution Function sensor [ Rème et al , , ] provided the ion data. We also used the magnetic data from POLAR [ Russell et al , ] and Geotail [ Kokubun et al , ] spacecraft, and data from the imaging middle atmosphere geophysical radar (IMAGER) for Magnetopause‐to‐Aurora Global Exploration (IMAGE) [ Gibson et al ., ].…”

Section: Instrumentsmentioning

confidence: 99%

Modulation of the substorm current wedge by bursty bulk flows: 8 September 2002—Revisited

et al. 2016

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The ultimate formation mechanism of the substorm current wedge (SCW) remains to date unclear. In this study, we investigate its relationship to plasma flows at substorm onset and throughout the following expansion phase. We revisit the case of 8 September 2002, which has been defined as “one of the best textbook examples of a substorm” because of its excellent coverage by both spacecraft in the magnetotail and ground‐based observatories. We found that a dense sequence of arrival of nightside flux transfer events (NFTEs; which can be understood as the lobe magnetic signature due to a bursty bulk flow travelling earthward in the central plasma sheet) in the near‐Earth tail leads to a modulation (and further step‐like builtup) of the SCW intensity during the substorm expansion phase. In addition, we found that small SCWs are created also during the growth phase of the event in association with another less intense sequence of NFTEs. The differences between the sequence of NFTEs in the growth and expansion phase are discussed. We conclude that the envelope of the magnetic disturbances which we typically refer to as an intense magnetic substorm is the result of a group or sequence of more intense and more frequent NFTEs.

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Section: Instrumentsmentioning

confidence: 99%

Modulation of the substorm current wedge by bursty bulk flows: 8 September 2002—Revisited

et al. 2016

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“…The Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) mission is dedicated to imaging the Earth's magnetosphere (Gibson et al, 2000). The Far Ultraviolet Camera Wideband Imaging Camera (WIC) provides global maps of the terrestrial aurora, in the spectral region from 140-190 nm.…”

Section: Instrumentationmentioning

confidence: 99%

Statistical study of high-latitude plasma flow during magnetospheric substorms

et al. 2004

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Abstract.We have utilised the near-global imaging capabilities of the Northern Hemisphere SuperDARN radars, to perform a statistical superposed epoch analysis of high-latitude plasma flows during magnetospheric substorms. The study involved 67 substorms, identified using the IMAGE FUV space-borne auroral imager. A substorm co-ordinate system was developed, centred on the magnetic local time and magnetic latitude of substorm onset determined from the auroral images. The plasma flow vectors from all 67 intervals were combined, creating global statistical plasma flow patterns and backscatter occurrence statistics during the substorm growth and expansion phases. The commencement of the substorm growth phase was clearly observed in the radar data 18-20 min before substorm onset, with an increase in the anti-sunward component of the plasma velocity flowing across dawn sector of the polar cap and a peak in the dawnto-dusk transpolar voltage. Nightside backscatter moved to lower latitudes as the growth phase progressed. At substorm onset a flow suppression region was observed on the nightside, with fast flows surrounding the suppressed flow region. The dawn-to-dusk transpolar voltage increased from ∼40 kV just before substorm onset to ∼75 kV 12 min after onset. The low-latitude return flow started to increase at substorm onset and continued to increase until 8 min after onset. The velocity flowing across the polar-cap peaked 12-14 min after onset. This increase in the flux of the polar cap and the excitation of large-scale plasma flow occurred even though the IMF B z component was increasing (becoming less negative) during most of this time. This study is the first to statistically prove that nightside reconnection creates magnetic flux and excites high-latitude plasma flow in a similar way to dayside reconnection and that dayside and nightside reconnection, are two separate time-dependent processes.

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“…High temporal resolution measurements of the aurora and geomagnetic field coupled with in situ spacecraft measurements in the critical locations in the magnetotail are needed to resolve this so‐called 2‐minute problem [e.g., Ohtani , 2004]. NASA's THEMIS (Time History of Events and Macroscale Interactions during Substorms) mission was specifically designed with this in mind [ Sibeck and Angelopoulos , 2008]; however, combinations of Cluster [ Escoubet et al , 2001], Double Star [ Liu et al , 2005], geosynchronous spacecraft, IMAGE (Imager for Magnetopause‐to‐Aurora Global Exploration) [ Gibson et al , 2000], and ground‐based observations are also well suited to solving the substorm problem.…”

Section: Introductionmentioning

confidence: 99%

Comprehensive ground‐based and in situ observations of substorm expansion phase onset

et al. 2010

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[1] In this paper, we present comprehensive ground-based and space-based in situ geosynchronous observations of a substorm expansion phase onset on 1 October 2005. The Double Star TC-2 and GOES-12 spacecraft were both located within the substorm current wedge during the substorm expansion phase onset, which occurred over the Canadian sector. We find that an onset of ULF waves in space was observed after onset on the ground by extending the AWESOME timing algorithm into space. Furthermore, a population of low-energy field-aligned electrons was detected by the TC-2 PEACE instrument contemporaneous with the ULF waves in space. These electrons appear to be associated with an enhancement of field-aligned Poynting flux into the ionosphere which is large enough to power visible auroral displays. The observations are most consistent with a near-Earth initiation of substorm expansion phase onset, such as the Near-Geosynchronous Onset (NGO) substorm scenario. A lack of data from further downtail, however, means other mechanisms cannot be ruled out.

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The Image Observatory

Cited by 8 publications

References 0 publications

Modulation of the substorm current wedge by bursty bulk flows: 8 September 2002—Revisited

Modulation of the substorm current wedge by bursty bulk flows: 8 September 2002—Revisited

Statistical study of high-latitude plasma flow during magnetospheric substorms

Comprehensive ground‐based and in situ observations of substorm expansion phase onset

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