caa a22 4500 445345942 CHVBK 20180317142829.0 cr unu---uuuuu 170323e20110501xx s 000 0 eng 10.1007/s11207-011-9753-2 doi (NATIONALLICENCE)springer-10.1007/s11207-011-9753-2 Relationship between the Parameters of Coronal Holes and High-Speed Solar Wind Streams over an Activity Cycle [Elektronische Daten] [V. Obridko, B. Shelting] The comparison of the brightness and area of coronal holes (CH) to the solar wind speed, which was started by Obridko et al. (Solar Phys. 260, 191, 2009a) has been continued. While the previous work was dealing with a relatively short time interval 2000 - 2006, here we have analyzed the data on coronal holes observed in the Sun throughout activity Cycle 23. A catalog of equatorial coronal holes has been compiled, and their brightness and area variations during the cycle have been analyzed. It is shown that CH is not merely an undisturbed zone between the active regions. The corona heating mechanism in CH seems to be essentially the same as in the regions of higher activity. The reduced brightness is the result of a specific structure with the magnetic field being quasi-radial at as low an altitude as 1.1R ⊙ or a bit higher. The plasma outflow decreases the measure of emission from CH. With an adequate choice of the photometric boundaries, the CH area and brightness indices display a fairly high correlation (0.6 - 0.8) with the solar wind velocity throughout the cycle, except for two years, which deviate dramatically - 2001 and 2007, i.e., the maximum and the minimum of the cycle. The mean brightness of the darkest part of CH, where the field lines are nearly radial at low altitudes, is of the order of 18 - 20% of the solar brightness, while the brightness of the other parts of the CH is 30 - 40%. The solar wind streams originate at the base of the coronal hole, which acts as an ejecting nozzle. The solar wind parameters in CH are determined at the level where the field lines are radial. Springer Science+Business Media B.V., 2011 Coronal hole nationallicence High-speed stream nationallicence Solar wind nationallicence Obridko V. Pushkov Institute of Terrestrial Magnetism, Ionosphere, and Radio Wave Propagation (IZMIRAN), Russian Academy of Sciences, Troitsk, Russia aut Shelting B. Pushkov Institute of Terrestrial Magnetism, Ionosphere, and Radio Wave Propagation (IZMIRAN), Russian Academy of Sciences, Troitsk, Russia aut Solar Physics Springer Netherlands 270/1(2011-05-01), 297-310 0038-0938 270:1<297 2011 270 11207 https://doi.org/10.1007/s11207-011-9753-2 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11207-011-9753-2 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Obridko V. Pushkov Institute of Terrestrial Magnetism, Ionosphere, and Radio Wave Propagation (IZMIRAN), Russian Academy of Sciences, Troitsk, Russia aut NATIONALLICENCE 700 1- Shelting B. Pushkov Institute of Terrestrial Magnetism, Ionosphere, and Radio Wave Propagation (IZMIRAN), Russian Academy of Sciences, Troitsk, Russia aut NATIONALLICENCE 773 0- Solar Physics Springer Netherlands 270/1(2011-05-01), 297-310 0038-0938 270:1<297 2011 270 11207 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer