Articles | Volume 19, issue 6
Special issue:
30 Jun 2001
 | 30 Jun 2001

Dense ion clouds of 0.1 − 2 keV ions inside the CPS-region observed by Astrid-2

S. H. Høymork, M. Yamauchi, Y. Ebihara, Y. Narita, O. Norberg, and D. Winningham

Abstract. Data from the Astrid-2 satellite taken between April and July 1999 show several examples of dense ion clouds in the 0.1–2 keV energy range inside the inner mag-netosphere, both in the northern and southern hemispheres. These inner magnetospheric ion clouds are found predomi-nantly in the early morning sector, suggesting that they could have originated from substorm-related ion injections on the night side. However, their location and density show no cor-relation with Kp, and their energy-latitude dispersion is not easily reproduced by a simple particle drift model. There-fore, these ion clouds are not necessarily caused by substorm-related ion injections. Alternative explanations for the ion clouds are the direct solar wind injections and up-welling ions from the other hemisphere. These explanations do not, however, account for all of the observations.

Key words. Magnetospheric physics (energetic particles, trapped; magnetospheric configuration and dynamics; storm and substorms)

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