The Extreme Ultraviolet Imager Investigation for the Image Mission

Sandel, B. R.; Broadfoot, A. L.; Curtis, C. C.; King, Robert A.; Stone, Tom; Hill, R. H.; Chen, J.; Siegmund, Oswald H. W.; Raffanti, Rick; Allred, David D.; Turley, R. Steven; Gallagher, D. L.

doi:10.1007/978-94-011-4233-5_7

Cited by 133 publications

(158 citation statements)

References 27 publications

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“…The IMAGE Extreme Ultraviolet Imager (EUV) (Sandel et al, 2000) images the distribution of He + in Earth's plasmasphere by detecting its resonantly-scattered emission at 30.4 nm. The plasmaspheric He + emission brightness is directly proportional to the He + column abundance, and thus can be used to estimate plasmapause location.…”

Section: Image Euv Satellite Observationsmentioning

confidence: 99%

An auroral westward flow channel (AWFC) and its relationship to field-aligned current, ring current, and plasmapause location determined using multiple spacecraft observations

Parkinson

Wild²,

Waters³

et al. 2007

Ann. Geophys.

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Abstract. An auroral westward flow channel (AWFC) is a latitudinally narrow channel of unstable F-region plasma with intense westward drift in the dusk-to-midnight sector ionosphere. AWFCs tend to overlap the equatorward edge of the auroral oval, and their life cycle is often synchronised to that of substorms: they commence close to substorm expansion phase onset, intensify during the expansion phase, and then decay during the recovery phase. Here we define for the first time the relationship between an AWFC, large-scale field-aligned current (FAC), the ring current, and plasmapause location. The Tasman International Geospace Environment Radar (TIGER), a Southern Hemisphere HF Super-DARN radar, observed a jet-like AWFC during ∼08:35 to 13:28 UT on 7 April 2001. The initiation of the AWFC was preceded by a band of equatorward expanding ionospheric scatter (BEES) which conveyed an intense poleward electric field through the inner plasma sheet. Unlike previous AWFCs, this event was not associated with a distinct substorm surge; rather it occurred during an interval of persistent, moderate magnetic activity characterised by AL∼ −200 nT. The four Cluster spacecraft had perigees within the dusk sector plasmasphere, and their trajectories were magnetically conjugate to the radar observations. The Waves of High frequency and Sounder for Probing Electron density by Relaxation (WHISPER) instruments on board Cluster were used to identify the plasmapause location. The Imager for Magnetopause-to-Aurora Global Exploration (IM-AGE) EUV experiment also provided global-scale observations of the plasmapause. The Cluster fluxgate magnetometers (FGM) provided successive measurements specifying the relative location of the ring current and filamentaryCorrespondence to: M. L. Parkinson (m.parkinson@latrobe.edu.au) plasma sheet current. An analysis of Iridium spacecraft magnetometer measurements provided estimates of large-scale ionospheric FAC in relation to the AWFC evolution. Peak flows in the AWFC were located close to the peak of a Region 2 downward FAC, located just poleward of the plasmapause. DMSP satellite observations confirmed the AWFC was located equatorward of the nightside plasmasheet, sometimes associated with ∼10 keV ion precipitation.

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Section: Image Euv Satellite Observationsmentioning

confidence: 99%

An auroral westward flow channel (AWFC) and its relationship to field-aligned current, ring current, and plasmapause location determined using multiple spacecraft observations

Parkinson

Wild²,

Waters³

et al. 2007

Ann. Geophys.

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“…The geomagnetic activity is unsteady during the few hours preceding the event (K p varying in both directions in the range 1 to 4). The global images of the plasmasphere taken by the Extreme Ultraviolet (EUV) instrument (Sandel et al, 2000) on the IMAGE mission (Burch, 2000) are not available at the precise time interval of our continuum observations. Because of IMAGE high apogee (∼7 R E ) and the EUV imager's wide field of view, images acquired near apogee show the structure of the entire plasmasphere.…”

Section: Case Of 9 July 2001: a Study At Medium Latitudementioning

confidence: 99%

Observation of continuum radiations from the Cluster fleet: first results from direction finding

et al. 2004

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Abstract. The Cluster fleet offers the first possibility of comparing non-thermal terrestrial continuum radiation from similarly equipped nearby observation points. A very rich data set has already been acquired on the Cluster polar orbit, between 4 and 19 Earth radii geocentric distances, and preliminary analysis has been carried out on these emissions. We focus in this paper on direction finding performed from all four spacecraft as a means to locate the position of the sources of this continuum radiation. Directions are derived from spin modulation properties, under the usual analysis assumptions of the wave vector of the radiation lying in the plane containing the spin axis and the antenna position at electric field minimum. All the spin axes of the four Cluster spacecraft are aligned perpendicular to the ecliptic, thus the aligned spacecraft antenna spin planes provide redundant 2-D views of the propagation path of the radiation and source location. Convincing 2-D triangulation results have been obtained in the vicinity of the source region. In addition, the out of spin plane component of the wave vector reveals itself to a certain extent through directivity characteristics compared at different distances of the spin plane to the ecliptic. The four case events studied (two of them taken near apogee, the other two near perigee) have confirmed general properties derived from previous observations: trapping in the lower frequency range, radiation escaping into the magnetosheath region in the higher frequency range. All propagation directions are compatible with source positions in the plasmapause region, however, at a significant distance from the equator in one case. Our observations have also revealed new properties, like the importance of small-scale density irregularities in the local amplification of continuum radiation. We conclude that more detailed generation and propagation models are needed to fit the observations.

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“…More recently, plumes have been routinely observed by the Extreme UltraViolet (EUV) imager (Sandel et al, 2000) onboard the IMAGE satellite (Garcia et al, 2003;Sandel et al, 2003;Goldstein et al, 2004;Goldstein and Sandel, 2005;Abe et al, 2006;Kim et al, 2007). Due to the EUV detection limit, plumes with a density lower than 40±10 cm −3 (Goldstein et al, 2003b) are missed by this imager.…”

Section: Introductionmentioning

confidence: 99%

Statistical analysis of plasmaspheric plumes with Cluster/WHISPER observations

et al. 2008

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Abstract. Plasmaspheric plumes have been routinely observed by the four Cluster spacecraft. This paper presents a statistical analysis of plumes observed during five years (from 1 February 2001 to 1 February 2006) based on fourpoint measurements of the plasmasphere (outside 4 Earth radii) as it is sampled by the spacecraft in a narrow local time sector before and after perigee. Plasmaspheric plumes can be identified from electron density profiles derived from the electron plasma frequency determined by the WHISPER wave sounder onboard Cluster. As the WHISPER instrument has a limited frequency range (2-80 kHz) only plumes with densities below 80 cm −3 can be identified in this way. Their occurrence is studied as a function of several geomagnetic indices (K p , am and D st ). Their transverse equatorial size, magnetic local time distribution, L position and density variation are discussed. Plasmaspheric plumes are observed mostly for moderate K p and never for small D st . They are found mainly in the afternoon and pre-midnight MLT sectors. Comparisons are also made between the density profiles of the plumes as they are crossed on the in-and outbound legs of the orbit, before and after perigee crossing, respectively.

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The Extreme Ultraviolet Imager Investigation for the Image Mission

Cited by 133 publications

References 27 publications

An auroral westward flow channel (AWFC) and its relationship to field-aligned current, ring current, and plasmapause location determined using multiple spacecraft observations

An auroral westward flow channel (AWFC) and its relationship to field-aligned current, ring current, and plasmapause location determined using multiple spacecraft observations

Observation of continuum radiations from the Cluster fleet: first results from direction finding

Statistical analysis of plasmaspheric plumes with Cluster/WHISPER observations

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