EDI electron time-of-flight measurements on Equator-S

Paschmann, G.; Sckopke, N.; Vaith, H.; Quinn, J. M.; Bauer, O. H.; Baumjohann, W.; Fillius, W.; Haerendel, G.; Kerr, S. S.; Kletzing, C. A.; Lynch, K.; McIlwain, C. E.; Torbert, R. B.; Whipple, E. C.

doi:10.1007/s00585-999-1513-3

Cited by 6 publications

(12 citation statements)

References 9 publications

(2 reference statements)

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“…Further development led to a time resolution much shorter than the spin period of the spacecraft [ Paschmann et al , 1997]. This improved Electron Drift Instrument (EDI) was first put aboard Equator‐S [ Quinn et al , 1999; Paschmann et al , 1999]. The same type of instrument was flown also on the Cluster spacecraft, which consist of four spacecraft (SC 1, 2, 3, and 4).…”

Section: Introductionmentioning

confidence: 99%

Electric field measurements in the inner magnetosphere by Cluster EDI

et al. 2003

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[1] We report electric field measurements in the inner magnetosphere from the Electron Drift Instrument (EDI) on Cluster at distances of 4 < L < 10. The data used in this study span more than 1 year so that all local times are covered. Both components of the electric field perpendicular to the ambient magnetic field are mapped into the equatorial plane with the magnetic field model of Tsyganenko and Stern [1996]. Average values and standard deviations are sorted by the polarity of the B Z component of the interplanetary magnetic field (IMF). Average Kp values for both B Z polarities are 1.45 (B Z > 0) and 2.45 (B Z < 0). These electric fields are discussed in terms of their sources such as the ionospheric dynamo and the solar wind-magnetosphere interaction. We also quantify the electric field as follows: the average shielding parameter g [Volland, 1973;Stern, 1975] is $2, although the value for southward IMF is smaller than the value for northward IMF. The parameter g is larger on the duskside than in the dawn sector. The average rate of sunward transport of magnetic flux, equivalent to the duskward electric field, is estimated as 0.32 mV/m for southward IMF. Finally, fluctuations tend to be larger than the DC component around the stagnation point, which could lead to outflow of plasmaspheric material.

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Section: Introductionmentioning

confidence: 99%

Electric field measurements in the inner magnetosphere by Cluster EDI

et al. 2003

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“…The EDI (Paschmann et al, 1997(Paschmann et al, , 2001) onboard Cluster consists of two electron gun/detector units placed on opposite sides of the spacecraft, similar to that flown on the Equator-S spacecraft (Paschmann et al, 1999). Amplitude-modulated electron beams are fired by the two guns in specific directions.…”

Section: R Nakamura Et Al: Fgm-edi Calibration Onboard Clustermentioning

confidence: 99%

“…The drift step, d = v d T g , during the gyration time T g (drift velocity: v d ) is a direct result from EDI measurements: small d can be determined by triangulation, based on the two beamfiring directions (for a detailed description see, Paschmann et al, 1997;Quinn et al, 1999). Large d are more accurately determined by time-of-flight observations of the two beams (Paschmann et al, 1997;Vaith et al, 1998).…”

Section: R Nakamura Et Al: Fgm-edi Calibration Onboard Clustermentioning

confidence: 99%

“…Large d are more accurately determined by time-of-flight observations of the two beams (Paschmann et al, 1997;Vaith et al, 1998). These times are different for electron release in parallel or anti-parallel directions to v d : T 1,2 = T g (1 ± |v d | / |v e |), where v e is the electron velocity dependent on their (known) kinetic energy: the sum of T 1 and T 2 yields twice the gyration time T g , their difference is proportional to d (Paschmann et al, 1999). The use of different electron energies further allows one to distinguish drifts caused by electric fields or magnetic field gradients (see, Paschmann et al, 1997).…”

Section: R Nakamura Et Al: Fgm-edi Calibration Onboard Clustermentioning

confidence: 99%

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Interinstrument calibration using magnetic field data from the flux-gate magnetometer (FGM) and electron drift instrument (EDI) onboard Cluster

Nakamura

Plaschke

Teubenbacher

et al. 2014

Geosci. Instrum. Method. Data Syst.

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Abstract.We compare the magnetic field data obtained from the flux-gate magnetometer (FGM) and the magnetic field data deduced from the gyration time of electrons measured by the electron drift instrument (EDI) onboard Cluster to determine the spin-axis offset of the FGM measurements. Data are used from orbits with their apogees in the magnetotail, when the magnetic field magnitude was between about 20 and 500 nT. Offset determination with the EDI-FGM comparison method is of particular interest for these orbits, because no data from solar wind are available in such orbits to apply the usual calibration methods using the Alfvén waves. In this paper, we examine the effects of the different measurement conditions, such as direction of the magnetic field relative to the spin plane and field magnitude in determining the FGM spin-axis offset, and also take into account the timeof-flight offset of the EDI measurements. It is shown that the method works best when the magnetic field magnitude is less than about 128 nT and when the magnetic field is aligned near the spin-axis direction. A remaining spin-axis offset of about 0.4 ∼ 0.6 nT was observed for Cluster 1 between July and October 2003. Using multipoint multi-instrument measurements by Cluster we further demonstrate the importance of the accurate determination of the spin-axis offset when estimating the magnetic field gradient.

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“…The triangulation is less accurate for small fields because the drift step becomes large compared to the triangulation base line (e.g. Paschmann et al (1999)). Additionally measurements of the difference of the times of flight for the two beams increase in accuracy; thus the drift velocity can be calculated more precisely.…”

Section: Introductionmentioning

confidence: 99%

In-flight calibration of the spin axis offset of a fluxgate magnetometer with an electron drift instrument

Leinweber¹,

Russell²,

Torkar³

2012

Meas. Sci. Technol.

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We show that the spin axis offset of a fluxgate magnetometer can be calibrated with an electron drift instrument (EDI) and that the required input time interval is relatively short. For missions such as Cluster or the upcoming Magnetospheric Multiscale (MMS) mission the spin axis offset of a fluxgate magnetometer could be determined on an orbital basis. An improvement of existing methods for finding spin axis offsets via comparison of accurate measurements of the field magnitude is presented, that additionally matches the gains of the two instruments that are being compared. The technique has been applied to EDI data from the Cluster Active Archive and fluxgate magnetometer data processed with calibration files also from the Cluster Active Archive. The method could prove to be valuable for the MMS mission because the four MMS spacecraft will only be inside the interplanetary field (where spin axis offsets can be calculated from Alfvénic fluctuations) for short periods of time and during unusual solar wind conditions.

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EDI electron time-of-flight measurements on Equator-S

Cited by 6 publications

References 9 publications

Electric field measurements in the inner magnetosphere by Cluster EDI

Electric field measurements in the inner magnetosphere by Cluster EDI

Interinstrument calibration using magnetic field data from the flux-gate magnetometer (FGM) and electron drift instrument (EDI) onboard Cluster

In-flight calibration of the spin axis offset of a fluxgate magnetometer with an electron drift instrument

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