A new result on the long lived sunspot magnetic flux and their association with CME speed

Abstract

In this article, we calculate sunspot magnetic flux and look for a connection with Coronal Mass Ejection (CME) speeds. The solar activity peaked between 2011 and 2016 in Solar Cycle 24, and we gathered long-term sunspot data from the northern and southern hemispheres during this period. Long-lived sunspots will undoubtedly be associated with flare-CME eruptions. Finding the relationship between the CME speed and the sunspot’s area and magnetic field is crucial to forecast CME speed in th near-Sun environment. We used solar charts from Kodaikanal solar observatory (KSO) and the square grid method to determine the sunspot’s area. We calculated the Line of Sight (LOS) magnetic field for every long-lived sunspot using magnetogram images from SDO/HMI for various locations for all the available observation days at KSO. According to this analysis, the sunspot area and flux are found to significantly impact the fast CMEs with speed ≥1000 km s −1. In the present study concerning the classification of sunspot types, we identified that βγ has long lived group of sunspots compared to other groups. The values of logarithmic magnetic flux (sunspot area x magnetic field) can be related with CME speeds as V CME = 754.29 x log(magnetic flux)-2888. The most important factor in determining the CME speeds is the values of the logarithmic magnetic flux. At smaller logarithmic magnetic flux values (≤5 MHS G) and faster CMEs (≥1000 km s −1), the magnetic flux has a better correlation with the CME speed.