North-South Asymmetry in the Solar Coronal Rotation

The solar images at 17 GHz by Nobeyama Radio Heliograph and in X-ray by soft X-ray telescope (SXT) on board Yohkoh satellite have been of particular interest for the estimation of solar coronal rotation using flux modulation approach. These studies established that the solar corona rotates differentially. The radio images estimate equatorial rotation period lower than those estimated by the X-ray images. The latitude profiles of the coronal rotation have temporal variability. The space-time plots of sidereal rotation period, interestingly, display clear North-South asymmetry. The asymmetry appears to change its sign in odd and even activity cycles of the Sun.