2024-09-10T01:05:59.983589Z http://sot.lmsal.com Mr. Sam Freeland Lockheed Martin Solar and Astrophysics Laboratory (LMSAL) http://www.lmsal.com Lockheed Martin ATC, 3251 Hanover St., Palo Alto, CA 94306 null null HINODE SOTSP Tohbans: Arikawa Planner: Sterling Observer: Morinaga 31 HOP 31 Coronal Hole Boundary Coronal Hole CH CH 11 20071117_003517 84 106 106 11 86 600 2 2 1 0 2 22 2029 295 0.9833333333333333 804.477 -110.522 93.515 162.304 2007-11-17T00:35:17.000Z 2007-11-17T00:53:55.000Z 804.477 -110.522 SUMER campaign- Coronal holes boundaries evolution Fast map 100 arcsec Scientific justification: Because of the different rotational profiles in the corona and at photospheric level and the fact that coronal hole boundaries separate two topologically different magnetic field configurations (open and closed), coronal hole boundaries are presumably the region where a continuous opening and closing of magnetic field lines takes place. This reconfiguration is believed to happen through magnetic reconnection between the open magnetic flux of the coronal hole and the closed one of the quiet Sun. Madjarska, Doyle and; van Driel-Gesztelyi (2004, ApJ, 603, 57) found the first evidence for magnetic reconnection along coronal hole boundaries using SUMER observations in spectral lines formed at transition region temperatures. Wang and; Sheely (2004, ApJ, 1196), however, believe that the reconnection takes place very high in the solar atmosphere (~ 2.5R), and that it occurs continuously in the form of small, stepwise displacements of field lines. A very important part of the present research will be the search for the origin of the slow solar wind. The helmet-streamer loops are considered as a possible source of the slow solar wind but with the major component coming from the coronal hole boundaries. With this present study, we want to observe equatorial coronal hole boundaries in order to find spectroscopic signatures of the physical processes which take place using simultaneously SUMER/EIS observations which will permit observations in spectral lines covering a large temperature range (from 40 000 K to a few million degrees). TRACE and XRT/Hinode will provide high resolution imaging in EUV and X-ray, respectively. MDI and SOT magnetic field data are crucial for this study. The study will combine spectroscopy and imaging and thanks to the high resolution vector magnetograms we can derive the geometry and the 3D scaling via magnetic field extrapolation (Wiegelmann, 2004, Solar Phys. 219, 87). The STEREO EUV and coronagraph observations will provide the necessary observational material for studying the connection between the coronal hole boundaries evolution and the slow solar wind generation. Target - equatorial coronal hole boundaries at three consecutive positions: at disk center, W40-W50 degrees and limb. Additionally quiet Sun region observations before or after in order to be used as a reference.