Statistics of high-altitude and high-latitude O+ ion outflows observed by Cluster/CIS

Other literature type English OPEN
Arvelius, S. ; Yamauchi, M. ; Nilsson, H. ; Lundin, R. ; Hobara, Y. ; Rème, H. ; Bavassano-Cattaneo, M.B. ; Paschmann, G. ; Korth, A. ; Kistler, L. M. ; Parks, G. K. (2005)
  • Journal: (issn: 1432-0576, eissn: 1432-0576)
  • Related identifiers: doi: 10.5194/angeo-23-1909-2005
  • Subject:
    arxiv: Astrophysics::High Energy Astrophysical Phenomena | Astrophysics::Earth and Planetary Astrophysics | Physics::Space Physics | Astrophysics::Solar and Stellar Astrophysics

The persistent outflows of O<sup>+</sup> ions observed by the Cluster CIS/CODIF instrument were studied statistically in the high-altitude (from 3 up to 11 <i>R<sub>E</sub></i>) and high-latitude (from 70 to ~90 deg invariant latitude, ILAT) polar region. The principal results are: (1) Outflowing O<sup>+</sup> ions with more than 1keV are observed above 10 <i>R<sub>E</sub></i> geocentric distance and above 85deg ILAT location; (2) at 6-8 <i>R<sub>E</sub></i> geocentric distance, the latitudinal distribution of O<sup>+</sup> ion outflow is consistent with velocity filter dispersion from a source equatorward and below the spacecraft (e.g. the cusp/cleft); (3) however, at 8-12 <i>R<sub>E</sub></i> geocentric distance the distribution of O<sup>+</sup> outflows cannot be explained by velocity filter only. The results suggest that additional energization or acceleration processes for outflowing O<sup>+</sup> ions occur at high altitudes and high latitudes in the dayside polar region.<p> <b>Keywords.</b> Magnetospheric physics (Magnetospheric configuration and dynamics, Solar wind-magnetosphere interactions)
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