Active longitudes and coronal structures during the rising phase of the solar cycle Original Research Article

The longitudinal structure of the solar corona has been investigated during the transition period between solar cycles 22 and 23 and at the beginning of the current cycle 23 using the SOHO/EIT data obtained in 171 Å, 195 Å, 284 Å and 304 Å EUV lines. The EIT images were transformed into synoptic maps for each of the spectral lines, and for the 195Å/171Å line ratio, which is an index of the coronal temperature. The synoptic maps reveal stable longitudinal structures in the coronal intensities and temperature, that are related to large-scale magnetic field structures. We discuss the relation between the coronal and photospheric magnetic structures obtained from the SOHO and Kitt Peak Solar Observatory data, and compare the rotation rates of these structures with the rotation profile of the solar interior in order to determine the possible origin of the coronal structures.