 |
| Titel |
A statistical study of unstable particle populations in the global ringcurrent and their relation to the generation of high m ULF waves |
| VerfasserIn |
L. J. Baddeley, T. K. Yeoman, D. M. Wright, K. J. Trattner, B. J. Kellet |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
0992-7689
|
| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 22, no. 12 ; Nr. 22, no. 12 (2004-12-22), S.4229-4241 |
| Datensatznummer |
250015087
|
| Publikation (Nr.) |
 copernicus.org/angeo-22-4229-2004.pdf |
|
|
|
|
|
| Zusammenfassung |
The first statistical study of the unstable proton populations which contain "free energy" required to drive small-scale poloidal mode ULF waves in the
magnetosphere between L-shell locations of 6 and 9 is presented. The data
examined are all in the form of Ion Distribution Functions (IDFs) covering a
particle energy range of 0.025keV to 328keV, amassed over 2.5 years from
the TIMAS and CAMMICE (MICS) instruments on-board the Polar spacecraft. Any free
energy which is available to drive a resonant wave mode manifests itself as
a positive gradient region in the IDF. A new analysis technique applied to
the data, allows for the first time, the amount of free energy contained in
each IDF to be quantified. The results show that IDFs are a common
occurrence in the magnetosphere at these L-shells, although they are most
common in the dawn/pre-noon sector. Lower energy (10–45keV) protons are
the most commonly observed unstable populations and also contain the largest
amounts of free energy (>1010J). Positive gradient regions at
higher energies (>100keV) are rarely observed and also contain greatly
reduced free energies (<109J).
Key words. Magnetospheric physics (Energetic particles,
trapped; MHD waves and instabilities) – Space plasma
physics (wave-particle interactions) |
| |
|
| Teil von |
|
|
|
|
|
|
|
|