van Driel-Gesztelyi, L;
Culhane, JL;
Baker, D;
Démoulin, P;
Mandrini, CH;
DeRosa, ML;
Rouillard, AP;
... Vourlidas, A; + view all
(2012)
Magnetic topology of active regions and coronal holes: implications for coronal outflows and the solar wind.
Solar Physics
, 281
(1)
237 -262.
10.1007/s11207-012-0076-8.
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Abstract
During 2-18 January 2008 a pair of low-latitude opposite-polarity coronal holes (CHs) were observed on the Sun with two active regions (ARs) and the heliospheric plasma sheet located between them. We use the Hinode/EUV Imaging Spectrometer (EIS) to locate AR-related outflows and measure their velocities. Solar-Terrestrial Relations Observatory (STEREO) imaging is also employed, as are the Advanced Composition Explorer (ACE) in-situ observations, to assess the resulting impacts on the solar wind (SW) properties. Magnetic-field extrapolations of the two ARs confirm that AR plasma outflows observed with EIS are co-spatial with quasi-separatrix layer locations, including the separatrix of a null point. Global potential-field source-surface modeling indicates that field lines in the vicinity of the null point extend up to the source surface, enabling a part of the EIS plasma upflows access to the SW. We find that similar upflow properties are also observed within closed-field regions that do not reach the source surface. We conclude that some of plasma upflows observed with EIS remain confined along closed coronal loops, but that a fraction of the plasma may be released into the slow SW. This suggests that ARs bordering coronal holes can contribute to the slow SW. Analyzing the in-situ data, we propose that the type of slow SW present depends on whether the AR is fully or partially enclosed by an overlying streamer. © 2012 Springer Science+Business Media B.V.
| Type: | Article |
|---|---|
| Title: | Magnetic topology of active regions and coronal holes: implications for coronal outflows and the solar wind |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1007/s11207-012-0076-8 |
| Publisher version: | http://dx.doi.org/10.1007/s11207-012-0076-8 |
| Language: | English |
| Additional information: | The final publication is available at link.springer.com |
| 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 Physics and Astronomy 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/1368907 |
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