Cluster EDI convection measurements across the high-latitude plasma sheet boundary at midnight

Quinn, J. M.; Paschmann, G.; Torbert, R. B.; Vaith, H.; McIlwain, C. E.; Haerendel, G.; Bauer, O. H.; Bauer, Thomas; Baumjohann, W.; Fillius, W.; Foerster, M.; Frey, S.; Georgescu, E.; Kerr, S. S.; Kletzing, C. A.; Matsui, H.; Puhl-Quinn, P.; Whipple, E. C.

doi:10.5194/angeo-19-1669-2001

Cited by 26 publications

(31 citation statements)

References 16 publications

(14 reference statements)

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“…Our standard analysis is then to select all beams within a certain time-interval, typically one spacecraft spin (4 s) and to perform an automated determination of the drift step. For higher time resolution analysis, shorter intervals can be chosen (see Quinn et al, 2001, this issue).…”

Section: Analysis Methodsmentioning

confidence: 99%

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The Electron Drift Instrument on Cluster: overview of first results

et al. 2001

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Abstract. EDI measures the drift velocity of artificially injected electron beams. From this drift velocity, the perpendicular electric field and the local magnetic field gradients can be deduced when employing different electron energies. The technique requires the injection of two electron beams at right angles to the magnetic field and the search for those directions within the plane that return the beams to their associated detectors after one or more gyrations. The drift velocity is then derived from the directions of the two beams and/or from the difference in their times-of-flight, measured via amplitude-modulation and coding of the emitted electron beams and correlation with the signal from the returning electrons. After careful adjustment of the control parameters, the beam recognition algorithms, and the onboard magnetometer calibrations during the commissioning phase, EDI is providing excellent data over a wide range of conditions. In this paper, we present first results in a variety of regions ranging from the polar cap, across the magnetopause, and well into the magnetosheath.

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Section: Analysis Methodsmentioning

confidence: 99%

“…5. Results from the night sector are described in a companion paper (Quinn et al, 2001, this issue).…”

Section: Introductionmentioning

confidence: 99%

The Electron Drift Instrument on Cluster: overview of first results

et al. 2001

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“…The drift velocity is computed either from the direction of the beams (via triangulation) or from the difference in their times-of-flight. More details about EDI can be found in Paschmann et al (1997Paschmann et al ( , 2001) and Quinn et al (2001).…”

Section: Cluster Edi Datamentioning

confidence: 99%

Plasma convection in the magnetotail lobes: statistical results from Cluster EDI measurements

et al. 2008

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Abstract.A major part of the plasma in the Earth's magnetotail is populated through transport of plasma from the solar wind via the magnetotail lobes. In this paper, we present a statistical study of plasma convection in the lobes for different directions of the interplanetary magnetic field and for different geomagnetic disturbance levels. The data set used in this study consists of roughly 340 000 one-minute vector measurements of the plasma convection from the Cluster Electron Drift Instrument (EDI) obtained during the period February 2001 to June 2007. The results show that both convection magnitude and direction are largely controlled by the interplanetary magnetic field (IMF). For a southward IMF, there is a strong convection towards the central plasma sheet with convection velocities around 10 km s −1 . During periods of northward IMF, the lobe convection is almost stagnant. A B y dominated IMF causes a rotation of the convection patterns in the tail with an oppositely directed dawn-dusk component of the convection for the northern and southern lobe. Our results also show that there is an overall persistent duskward component, which is most likely a result of conductivity gradients in the footpoints of the magnetic field lines in the ionosphere.

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“…The EDI technique, hardware, operation, and data analysis method have been described in detail in earlier publications (Paschmann et al, 1997;Quinn et al, 2001;Paschmann et al, 2001). Briefly, the technique is based on the injection of two electron beams at right angles to the ambient magnetic field, and the search of the two directions (within the B ⊥ -plane) that return the beams to their associated detectors after one or more gyrations.…”

Section: Instrumentation and Data Analysismentioning

confidence: 99%

Plasma convection across the polar cap, plasma mantle and cusp: Cluster EDI observations

et al. 2004

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Abstract. In this paper we report measurements of the polar cap convection obtained with the Electron Drift Instrument (EDI) on Cluster. We use 20 passes that cross the polar cap between its dayside and nightside boundaries (or vice versa) at geocentric distances ranging from about 5 to about 13 R E , and at interspacecraft separations (transverse to the ambient magnetic field) between a few km and almost 10 000 km. We first illustrate the nature of the data by presenting four passes in detail. They demonstrate that the sense of convection (anti-sunward vs. sunward) essentially agrees with the expectations based on magnetic reconnection occurring on the dayside or poleward of the cusp. The most striking feature in the EDI data is the occurrence of largeamplitude fluctuations that are superimposed on the average velocities. One type of fluctuation appears to grow when approaching the dayside polar cap boundary. The examples also show that there is a variable degree of inter-spacecraft correlation, ranging from excellent to poor. We then present statistical results on all 20 passes. Plotting 10-min averages of the convection velocities vs. IMF B z one recovers the expected dependence, albeit with large scatter. Looking at the variances computed over the same 10-min intervals, one confirms that there is indeed one type of contribution that grows towards the dayside boundary, but that variances can be high anywhere. Finally, computing the inter-spacecraft correlations as a function of their separation distance transverse to the magnetic field shows that the average correlation drops with increasing distance, but that even at distances as large as 5000 km the correlation can be very good. To put those scales into context, the separation distances have also been scaled to ionospheric altitudes where they range between a few hundred meters and 600 km.

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Cluster EDI convection measurements across the high-latitude plasma sheet boundary at midnight

Cited by 26 publications

References 16 publications

The Electron Drift Instrument on Cluster: overview of first results

The Electron Drift Instrument on Cluster: overview of first results

Plasma convection in the magnetotail lobes: statistical results from Cluster EDI measurements

Plasma convection across the polar cap, plasma mantle and cusp: Cluster EDI observations

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