Culhane, JL;
Brooks, DH;
van Driel-Gesztelyi, L;
Démoulin, P;
Baker, D;
DeRosa, ML;
Mandrini, CH;
... Zurbuchen, TH; + view all
(2014)
Tracking Solar Active Region Outflow Plasma from Its Source to the Near-Earth Environment.
Solar Physics
, 289
(10)
pp. 3799-3816.
10.1007/s11207-014-0551-5.
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Abstract
Seeking to establish whether active-region upflow material contributes to the slow solar wind, we examine in detail the plasma upflows from Active Region (AR) 10978, which crossed the Sun's disc in the interval 8 to 16 December 2007 during Carrington rotation (CR) 2064. In previous work, using data from the Hinode/EUV Imaging Spectrometer, upflow velocity evolution was extensively studied as the region crossed the disc, while a linear force-free-field magnetic extrapolation was used to confirm aspects of the velocity evolution and to establish the presence of quasi-separatrix layers at the upflow source areas. The plasma properties, temperature, density, and first ionisation potential bias [FIP-bias] were measured with the spectrometer during the disc passage of the active region. Global potential-field source-surface (PFSS) models showed that AR 10978 was completely covered by the closed field of a helmet streamer that is part of the streamer belt. Therefore it is not clear how any of the upflowing AR-associated plasma could reach the source surface at 2.5 R ⊙ and contribute to the slow solar wind. However, a detailed examination of solar-wind in-situ data obtained by the Advanced Composition Explorer (ACE) spacecraft at the L 1 point shows that increases in O 7+ /O 6+ , C 6+ /C 5+ , and Fe/O - a FIP-bias proxy - are present before the heliospheric current-sheet crossing. These increases, along with an accompanying reduction in proton velocity and an increase in density are characteristic of both AR and slow-solar-wind plasma. Finally, we describe a two-step reconnection process by which some of the upflowing plasma from the AR might reach the heliosphere. © 2014 The Author(s).
| Type: | Article |
|---|---|
| Title: | Tracking Solar Active Region Outflow Plasma from Its Source to the Near-Earth Environment |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1007/s11207-014-0551-5 |
| Publisher version: | https://doi.org/10.1007/s11207-014-0551-5 |
| Language: | English |
| Additional information: | This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ |
| Keywords: | Active region upflow, Magnetic topology, Slow solar wind contribution |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
| URI: | https://discovery.ucl.ac.uk/id/eprint/1436517 |
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