North-South Asymmetry in the Solar Coronal Rotation

TL;DR

This study investigates the North-South asymmetry in solar coronal rotation using radio and X-ray observations, revealing temporal variability and cycle-dependent sign changes in the asymmetry.

Contribution

It provides new insights into the asymmetry and temporal variability of solar coronal rotation across different solar activity cycles.

Findings

Detected clear North-South asymmetry in coronal rotation.

Observed sign changes in asymmetry between odd and even solar cycles.

Identified variability in rotation profiles over time.

Abstract

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.