Equatorial coronal holes and their relation to the high-speed solar wind streams [Elektronische Ressource] / vorgelegt von Lidong Xia

Equatorial Coronal Holes and Their Relation to theHigh Speed Solar Wind StreamsDissertationzur Erlangung des Doktorgradesder Mathematisch Naturwissenschaftlichen Fakultaten¨der Georg August Universit at¨ zu Gotting¨ envorgelegt vonLidong XiaausKaihua/ChinaGotti¨ ngen 2003D7Referent: Prof. Dr. Franz KneerKorreferent: Prof. Dr. Eckart MarschTag der mun¨ dlichen Pru¨fung: 22. Mai 2003Dedicated to Yiling and MinlanAbstractThe heating of the solar corona and the origin and acceleration of the solar wind are amongthe important unsolved problems of space plasma and solar physics. Coronal holes (CHs)have been known as the source of the fast solar wind. However, the plasma properties atthe base of CHs have not yet been fully understood. The purpose of this thesis work isto study equatorial CHs and their relation to the origin and propagation of the high speedsolar wind streams by combining observations with both space based (SOHO and WIND)and ground based (NSO/KP) instruments. With the high spectral and spatial resolution ofSUMER on SOHO, the morphology of equatorial CHs was investigated and comparedwith the quiet Sun region by deducing 2 D images in ultraviolet emission line parameters(intensity, Doppler shift and width), which provide useful information about the plasmaproperties in different layers of the solar atmosphere.