The cusp: a window for particle exchange between the radiation belt and the solar wind
The study focuses on a single particle dynamics in the cusp region. The topology of the cusp region in terms of magnetic field iso-B contours has been studied using the Tsyganenko 96 model (T96) as an example, to show the importance of an off-equatorial minimum on particle trapping. We carry out...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2006-11-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/24/3131/2006/angeo-24-3131-2006.pdf |
| _version_ | 1819181421151911936 |
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| author | X.-Z. Zhou X.-Z. Zhou T. A. Fritz Q.-G. Zong Q.-G. Zong Z. Y. Pu Y.-Q. Hao J.-B. Cao |
| author_facet | X.-Z. Zhou X.-Z. Zhou T. A. Fritz Q.-G. Zong Q.-G. Zong Z. Y. Pu Y.-Q. Hao J.-B. Cao |
| author_sort | X.-Z. Zhou |
| collection | DOAJ |
| description | The study focuses on a single particle dynamics in the cusp
region. The topology of the cusp region in terms of magnetic field
iso-B contours has been studied using the Tsyganenko 96 model
(T96) as an example, to show the importance of an off-equatorial
minimum on particle trapping. We carry out test particle
simulations to demonstrate the bounce and drift motion. The "cusp
trapping limit" concept is introduced to reflect the particle
motion in the high latitude magnetospheric region. The spatial
distribution of the "cusp trapping limit" shows that only those
particles with near 90° pitch-angles can be trapped and
drift around the cusp. Those with smaller pitch angles may be
partly trapped in the iso-B contours, however, they will
eventually escape along one of the magnetic field lines. There
exist both open field lines and closed ones within the same drift
orbit, indicating two possible destinations of these particles:
those particles being lost along open field lines will be
connected to the surface of the magnetopause and the solar wind,
while those along closed ones will enter the equatorial radiation
belt. Thus, it is believed that the cusp region can provide a
window for particle exchange between these two regions. Some of
the factors, such as dipole tilt angle, magnetospheric convection,
IMF and the Birkeland current system, may influence the cusp's
trapping capability and therefore affect the particle exchanging
mechanism. Their roles are examined by both the analysis of cusp
magnetic topology and test particle simulations. |
| first_indexed | 2024-12-22T22:29:58Z |
| format | Article |
| id | doaj.art-c9a7c43c659e46739f32c65ec32f02bb |
| institution | Directory Open Access Journal |
| issn | 0992-7689 1432-0576 |
| language | English |
| last_indexed | 2024-12-22T22:29:58Z |
| publishDate | 2006-11-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Annales Geophysicae |
| spelling | doaj.art-c9a7c43c659e46739f32c65ec32f02bb2022-12-21T18:10:28ZengCopernicus PublicationsAnnales Geophysicae0992-76891432-05762006-11-01243131313710.5194/angeo-24-3131-2006The cusp: a window for particle exchange between the radiation belt and the solar windX.-Z. Zhou0X.-Z. Zhou1T. A. Fritz2Q.-G. Zong3Q.-G. Zong4Z. Y. Pu5Y.-Q. Hao6J.-B. Cao7Institute of Space Physics and Applied Technology, Peking University, Beijing 100871, ChinaKey Laboratory for Space Weather, Chinese Academy of Sciences, Beijing, ChinaCenter for Space Physics, Boston University, Boston, MA 02215, USAKey Laboratory for Space Weather, Chinese Academy of Sciences, Beijing, ChinaCenter for Atmospheric Research, University of Massachusetts, Lowell, MA 01854, USAInstitute of Space Physics and Applied Technology, Peking University, Beijing 100871, ChinaInstitute of Space Physics and Applied Technology, Peking University, Beijing 100871, ChinaKey Laboratory for Space Weather, Chinese Academy of Sciences, Beijing, ChinaThe study focuses on a single particle dynamics in the cusp region. The topology of the cusp region in terms of magnetic field iso-B contours has been studied using the Tsyganenko 96 model (T96) as an example, to show the importance of an off-equatorial minimum on particle trapping. We carry out test particle simulations to demonstrate the bounce and drift motion. The "cusp trapping limit" concept is introduced to reflect the particle motion in the high latitude magnetospheric region. The spatial distribution of the "cusp trapping limit" shows that only those particles with near 90° pitch-angles can be trapped and drift around the cusp. Those with smaller pitch angles may be partly trapped in the iso-B contours, however, they will eventually escape along one of the magnetic field lines. There exist both open field lines and closed ones within the same drift orbit, indicating two possible destinations of these particles: those particles being lost along open field lines will be connected to the surface of the magnetopause and the solar wind, while those along closed ones will enter the equatorial radiation belt. Thus, it is believed that the cusp region can provide a window for particle exchange between these two regions. Some of the factors, such as dipole tilt angle, magnetospheric convection, IMF and the Birkeland current system, may influence the cusp's trapping capability and therefore affect the particle exchanging mechanism. Their roles are examined by both the analysis of cusp magnetic topology and test particle simulations.https://www.ann-geophys.net/24/3131/2006/angeo-24-3131-2006.pdf |
| spellingShingle | X.-Z. Zhou X.-Z. Zhou T. A. Fritz Q.-G. Zong Q.-G. Zong Z. Y. Pu Y.-Q. Hao J.-B. Cao The cusp: a window for particle exchange between the radiation belt and the solar wind Annales Geophysicae |
| title | The cusp: a window for particle exchange between the radiation belt and the solar wind |
| title_full | The cusp: a window for particle exchange between the radiation belt and the solar wind |
| title_fullStr | The cusp: a window for particle exchange between the radiation belt and the solar wind |
| title_full_unstemmed | The cusp: a window for particle exchange between the radiation belt and the solar wind |
| title_short | The cusp: a window for particle exchange between the radiation belt and the solar wind |
| title_sort | cusp a window for particle exchange between the radiation belt and the solar wind |
| url | https://www.ann-geophys.net/24/3131/2006/angeo-24-3131-2006.pdf |
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