Coronal holes and photospheric magnetic fields

Magnetic field observations reported by Hoeksema and Scherrer (1986) were used to examine the mutual arrangement of coronal holes recorded in the 10830 He I line during the fall-off phase (1982-1985) of the 21st solar cycle, relative to the large-scale photospheric and coronal magnetic fields. Results show that the coronal holes change in phase with the total solar radiation flux in the Ca II line, indicating their common nature. A mechanism for heating coronal holes, similar to that proposed by Pikel'ner (1960), is discussed.