title: Solar wind origin in coronal funnels.
abstract: The origin of the solar wind in solar coronal holes has long been unclear. We establish that the solar wind starts flowing out of the corona at heights above the photosphere between 5 megameters and 20 megameters in magnetic funnels. This result is obtained by a correlation of the Doppler-velocity and radiance maps of spectral lines emitted by various ions with the force-free magnetic field as extrapolated from photospheric magnetograms to different altitudes. Specifically, we find that Ne7+ ions mostly radiate around 20 megameters, where they have outflow speeds of about 10 kilometers per second, whereas C3+ ions with no average flow speed mainly radiate around 5 megameters. Based on these results, a model for understanding the solar wind origin is suggested.
authors.affiliation: Department of Geophysics, Peking University, Beijing 100871, China. cytu@public3.bta.net.cn
authors.forename: Chuan-Yi
authors.initials: CY
authors.lastname: Tu
authors.forename: Cheng
authors.initials: C
authors.lastname: Zhou
authors.forename: Eckart
authors.initials: E
authors.lastname: Marsch
authors.forename: Li-Dong
authors.initials: LD
authors.lastname: Xia
authors.forename: Liang
authors.initials: L
authors.lastname: Zhao
authors.forename: Jing-Xiu
authors.initials: JX
authors.lastname: Wang
authors.forename: Klaus
authors.initials: K
authors.lastname: Wilhelm