Current Polar Activity of the Sun and Its implications for Solar Cycle 25

Abstract:

Polar activity of one solar cycle is known to indicate certain characteristics of the subsequent cycle in terms of strength (e.g., Sunspot number) and phase. In particular the polar field strength (or its proxies such as the microwave polar brightness) during the minimum phase of seem to be well correlated with the maximum sunspot number of the next cycle. Polar prominence eruptions and coronal mass ejections have also been found to be important indicators of the time of polarity reversal. While these indicators are present in the current cycle, significant differences are found regarding the phase lag between the two hemispheres and the duration of polar eruptions. We use prominence eruption data from the Nobeyama Radioheliograph and the Solar Dynamics Observatory to highlight these differences. We also use the polar microwave brightness variation and discuss the implications to solar cycle 25.