Magnetic Topology of Active Regions and Coronal Holes: Implications for Coronal Outflows and the Solar Wind |
| |
Authors: | L van Driel-Gesztelyi J L Culhane D Baker P Démoulin C H Mandrini M L DeRosa A P Rouillard A Opitz G Stenborg A Vourlidas D H Brooks |
| |
Institution: | 1. Mullard Space Science Laboratory, University College London, Dorking, UK 2. Observatoire de Paris, LESIA, CNRS, UPMC Univ. Paris 06, Univ. Paris-Diderot, Meudon, France 3. Konkoly Observatory, Hungarian Academy of Sciences, Budapest, Hungary 4. International Space Science Institute, Bern, Switzerland 5. Instituto de Astronom??a y F??sica del Espacio, CONICET-UBA, CC. 67, Suc. 28, 1428, Buenos Aires, Argentina 6. Facultad de Ciencias Exactas y Naturales, FCEN-UBA, Buenos Aires, Argentina 7. Lockheed Martin Solar and Astrophysics Laboratory, Palo Alto, CA, 94304, USA 8. Institut de Recherche en Astrophysique et Plan??tologie, Universit?? de Toulouse (UPS), Toulouse, France 9. Centre National de la Recherche Scientifique, UMR 5277, Toulouse, France 10. College of Science, George Mason University, Fairfax, VA, 22030, USA 11. Space Science Division, Naval Research Laboratory, Washington, DC, 20375, USA
|
| |
Abstract: | During 2??C?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. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|