Oxygen Beams In The Polar Cap and Cusp Regions:multi-spacecraft Observations By Cis Cluster
Abstract
During winter and spring 2001 oxygen beams were frequently observed with the CIS experiment onboard Cluster in the cusp and polar cap regions. The observations showed similar features of oxygen outflow for all these events: the beams show a nar- row energy distribution with energy dispersion. The energy varies from 1000 eV in the cusp to 30 eV in the polar cap. The observed oxygen beam can be interpreted as a superposition of the field-aligned motion of O+ with V from a localized ionospheric source in the cusp region with plasma convection with V. In this paper we will con- centrate on one event, 18 May 2001, 02:00-03:15 UT. During this time oxygen beams were detected on three S/C simultaneously. The separation distances between the S/C were rather high, between 1 and 3 Re. This observation gives us the unique possibility to estimate the spatial size of the oxygen source in the ionosphere and to study the spatial variations of the oxygen outflow.
- Publication:
-
EGS General Assembly Conference Abstracts
- Pub Date:
- 2002
- Bibcode:
- 2002EGSGA..27.4170B