Electron Heat Flux in Pressure Balance Structures Observed by Ulysses
Abstract
Pressure balance structures (PBSs) are a common feature in the high-latitude solar wind near solar minimum. From previous studies, PBSs are believed to be remnants of coronal plumes and be related to network activity such as magnetic reconnection in the photosphere. We investigated the magnetic structures of the PBSs, applying a minimum variance analysis to Ulysses/Magnetometer data. At 2001 AGU Spring meeting, we reported that PBSs have structures like current sheets or plasmoids, and suggested that they are associated with network activity at the base of polar plumes. In this paper, we have analyzed high-energy electron data at Ulysses/SWOOPS to see whether bi-directional electron flow exists and confirm the conclusions more precisely. As a result, although most events show a typical flux directed away from the Sun, some PBSs show bi-directional electron flux and others show an isotropic distribution of electron pitch angles. Therefore, we can conclude that plasmoids are flowing away from the Sun, changing their flow direction dynamically in a way not caused by Alfvén waves. From this, we may conclude that PBSs are generated due to network activity at the base of polar plumes and their magnetic structures are like current sheets or plasmoids.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2001
- Bibcode:
- 2001AGUFMSH32A0733Y
- Keywords:
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- 2116 Energetic particles;
- planetary;
- 2134 Interplanetary magnetic fields;
- 2164 Solar wind plasma;
- 7511 Coronal holes;
- 7811 Discontinuities