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| Titel |
Interinstrument calibration using magnetic field data from the flux-gate magnetometer (FGM) and electron drift instrument (EDI) onboard Cluster |
| VerfasserIn |
R. Nakamura, F. Plaschke, R. Teubenbacher, L. Giner, W. Baumjohann, W. Magnes, M. Steller, R. B. Torbert, H. Vaith, M. Chutter, K.-H. Fornacon, K.-H. Glassmeier, C. Carr |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
2193-0856
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| Digitales Dokument |
URL |
| Erschienen |
In: Geoscientific Instrumentation, Methods and Data Systems ; 3, no. 1 ; Nr. 3, no. 1 (2014-01-22), S.1-11 |
| Datensatznummer |
250115207
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| Publikation (Nr.) |
 copernicus.org/gi-3-1-2014.pdf |
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| Zusammenfassung |
| 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 time-of-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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