SOLAR FEATURES STUDIED FROM THE GROUND AND ON THE CORONAS-F SATELLITE. PART 2. MAGNETIC FIELDS AT VARIOUS HEIGHTS IN CORONAL HOLES

摘要

Simultaneous space and ground observations have been used in analyzing the magnetic fields in coronal holes at various heights in the Sun's atmosphere. Data have been used from the SPIRIT instruments on the CORONAS-F spacecraft and from the universal spectrograph on the BST-2 telescope at CAO. The following results have been obtained: Within a single approach, a method has been developed for identifying coronal holes and determining their areas from observations on the Sun in the spectral lines 10830 A Fe IX-X 171 A, Fe XI-XH 195 A, Fe XV 284 A. Examples are given of various changes in area with height in coronal holes. It is shown that a coronal hole whose area increases with height is almost completely in a region of an open magnetic tube, whereas almost all coronal holes whose areas decrease with height are in the regions of closed field lines. At the photosphere level, the region of inclusions of magnetic field opposite in sign to the main field of the coronal hole attain 20-25% of the coronal hole area. The magnetic field of a coronal hole becomes unipolar at heights of 25-30 thousand km.