Four-spacecraft determination of magnetopause orientation, motion and thickness: comparison with results from single-spacecraft methods
In this paper, we use Cluster data from one magnetopause event on 5 July 2001 to compare predictions from various methods for determination of the velocity, orientation, and thickness of the magnetopause current layer. We employ established as well as new multi-spacecraft techniques, in which ti...
| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2004-04-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/22/1347/2004/angeo-22-1347-2004.pdf |
| _version_ | 1818275305095168000 |
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| author | S. E. Haaland S. E. Haaland B. U. Ö. Sonnerup M. W. Dunlop A. Balogh E. Georgescu H. Hasegawa B. Klecker G. Paschmann G. Paschmann P. Puhl-Quinn H. Rème H. Vaith A. Vaivads |
| author_facet | S. E. Haaland S. E. Haaland B. U. Ö. Sonnerup M. W. Dunlop A. Balogh E. Georgescu H. Hasegawa B. Klecker G. Paschmann G. Paschmann P. Puhl-Quinn H. Rème H. Vaith A. Vaivads |
| author_sort | S. E. Haaland |
| collection | DOAJ |
| description | In this paper, we use Cluster data
from one magnetopause event on 5 July 2001 to compare predictions from various
methods for determination of the velocity, orientation, and thickness of the
magnetopause current layer. We employ established as well as new
multi-spacecraft techniques, in which time differences between the crossings
by the four spacecraft, along with the duration of each crossing, are used to
calculate magnetopause speed, normal vector, and width. The timing is based on
data from either the Cluster Magnetic Field Experiment (FGM) or the Electric
Field Experiment (EFW) instruments.
The multi-spacecraft results are compared with those derived from
various single-spacecraft techniques, including minimum-variance analysis of
the magnetic field and deHoffmann-Teller, as well as Minimum-Faraday-Residue
analysis of plasma velocities and magnetic fields measured during the
crossings. In order to improve the overall consistency between multi-
and single-spacecraft results, we have also explored the use of hybrid
techniques, in which timing information from the four spacecraft is combined
with certain limited results from single-spacecraft methods, the remaining
results being left for consistency checks.
The results show good agreement between magnetopause orientations derived from
appropriately chosen single-spacecraft techniques and those obtained from
multi-spacecraft timing. The agreement between magnetopause speeds derived from
single- and multi-spacecraft methods is quantitatively somewhat less good but it is
evident that the speed can change substantially from one crossing to the next
within an event. The magnetopause thickness varied substantially from
one crossing to the next, within an event. It ranged from 5 to 10 ion gyroradii.
The density profile was sharper than the magnetic profile: most of the density
change occured in the earthward half of the magnetopause.<br><br>
<b>Key words.</b> Magnetospheric physics (magnetopause, cusp
and boundary layers; instruments and techniques) – Space
plasma physics (discontinuities) |
| first_indexed | 2024-12-12T22:27:38Z |
| format | Article |
| id | doaj.art-7b0cce7101be465cb30bb82895309c64 |
| institution | Directory Open Access Journal |
| issn | 0992-7689 1432-0576 |
| language | English |
| last_indexed | 2024-12-12T22:27:38Z |
| publishDate | 2004-04-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Annales Geophysicae |
| spelling | doaj.art-7b0cce7101be465cb30bb82895309c642022-12-22T00:09:42ZengCopernicus PublicationsAnnales Geophysicae0992-76891432-05762004-04-01221347136510.5194/angeo-22-1347-2004Four-spacecraft determination of magnetopause orientation, motion and thickness: comparison with results from single-spacecraft methodsS. E. Haaland0S. E. Haaland1B. U. Ö. Sonnerup2M. W. Dunlop3A. Balogh4E. Georgescu5H. Hasegawa6B. Klecker7G. Paschmann8G. Paschmann9P. Puhl-Quinn10H. Rème11H. Vaith12A. Vaivads13Max-Planck Institute für extraterrestrische Physik (MPE), Garching, GermanyInternational Space Science Institute (ISSI), Bern, SwitzerlandDartmouth College, Hanover, NH, USARutherford-Appleton Labs, Oxford, UKImperial College, London, UKMax-Planck Institute für extraterrestrische Physik (MPE), Garching, GermanyDartmouth College, Hanover, NH, USAMax-Planck Institute für extraterrestrische Physik (MPE), Garching, GermanyMax-Planck Institute für extraterrestrische Physik (MPE), Garching, GermanyInternational Space Science Institute (ISSI), Bern, SwitzerlandMax-Planck Institute für extraterrestrische Physik (MPE), Garching, GermanyCentre d’Étude Spatiale des Rayonnements (CESR), Toulouse, FranceMax-Planck Institute für extraterrestrische Physik (MPE), Garching, GermanySwedish Institute of Space Physics, Uppsala, SwedenIn this paper, we use Cluster data from one magnetopause event on 5 July 2001 to compare predictions from various methods for determination of the velocity, orientation, and thickness of the magnetopause current layer. We employ established as well as new multi-spacecraft techniques, in which time differences between the crossings by the four spacecraft, along with the duration of each crossing, are used to calculate magnetopause speed, normal vector, and width. The timing is based on data from either the Cluster Magnetic Field Experiment (FGM) or the Electric Field Experiment (EFW) instruments. The multi-spacecraft results are compared with those derived from various single-spacecraft techniques, including minimum-variance analysis of the magnetic field and deHoffmann-Teller, as well as Minimum-Faraday-Residue analysis of plasma velocities and magnetic fields measured during the crossings. In order to improve the overall consistency between multi- and single-spacecraft results, we have also explored the use of hybrid techniques, in which timing information from the four spacecraft is combined with certain limited results from single-spacecraft methods, the remaining results being left for consistency checks. The results show good agreement between magnetopause orientations derived from appropriately chosen single-spacecraft techniques and those obtained from multi-spacecraft timing. The agreement between magnetopause speeds derived from single- and multi-spacecraft methods is quantitatively somewhat less good but it is evident that the speed can change substantially from one crossing to the next within an event. The magnetopause thickness varied substantially from one crossing to the next, within an event. It ranged from 5 to 10 ion gyroradii. The density profile was sharper than the magnetic profile: most of the density change occured in the earthward half of the magnetopause.<br><br> <b>Key words.</b> Magnetospheric physics (magnetopause, cusp and boundary layers; instruments and techniques) – Space plasma physics (discontinuities)https://www.ann-geophys.net/22/1347/2004/angeo-22-1347-2004.pdf |
| spellingShingle | S. E. Haaland S. E. Haaland B. U. Ö. Sonnerup M. W. Dunlop A. Balogh E. Georgescu H. Hasegawa B. Klecker G. Paschmann G. Paschmann P. Puhl-Quinn H. Rème H. Vaith A. Vaivads Four-spacecraft determination of magnetopause orientation, motion and thickness: comparison with results from single-spacecraft methods Annales Geophysicae |
| title | Four-spacecraft determination of magnetopause orientation, motion and thickness: comparison with results from single-spacecraft methods |
| title_full | Four-spacecraft determination of magnetopause orientation, motion and thickness: comparison with results from single-spacecraft methods |
| title_fullStr | Four-spacecraft determination of magnetopause orientation, motion and thickness: comparison with results from single-spacecraft methods |
| title_full_unstemmed | Four-spacecraft determination of magnetopause orientation, motion and thickness: comparison with results from single-spacecraft methods |
| title_short | Four-spacecraft determination of magnetopause orientation, motion and thickness: comparison with results from single-spacecraft methods |
| title_sort | four spacecraft determination of magnetopause orientation motion and thickness comparison with results from single spacecraft methods |
| url | https://www.ann-geophys.net/22/1347/2004/angeo-22-1347-2004.pdf |
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