11:30 AM - 11:45 AM
[PEM11-13] A Study on Magnetic Parameters to Determine the Formation of CME
Keywords:CME, Space Weather, Nonpotential Magnetic Field
Coronal Mass Ejection (CME) is an ejection of magnetic field and plasma mass from the solar corona into the heliosphere. CMEs are often associated with solar flare, but not always. Because CMEs are the major cause of space weather disturbance, the prediction of CME occurrence is a crucial issue, and many different studies have been conducted to find the condition of CME occurrence.
The objective of this paper is to investigate the various magnetic parameter to determine the formation of CME, focusing on the distribution of nonpotential magnetic field (BNP). To this end, not only parameters including the integrated parameters over whole active region (AR) but also the parameters focusing on the area satisfying BNP > 500G and BNP > 1000G are devised and evaluate how they well discriminate between the ARs producing eruptive flares associated with CME and confined flares not-associated with CME. To appraise their discrimination capability, I employ the receiver operating characteristic (ROC) curve and the area under curve (AUC). Moreover, I also calculate the AUC of the parameters proposed by the previous papers (Toriumi et al. 2017 and Lin et al. 2021) and compare their discrimination capabilities with our study.
In this study, the average magnetic flux density of AR (BAR), the average magnetic energy density of AR (ρAR) and some dimensionless quantities (called the λ-type and ω-type parameters) have high AUC (≧0.75). Especially, λ- and ω-type parameters used BNP of the area satisfying BNP > 500G perform well on AUC.
These results suggest that the area satisfying BNP > 500G is likely to be related to CME occurrence. Also, the fact that the parameters BAR and ρAR averaged over the AR are relatively better than the parameters given by the integration over the AR is consistent with the tendency that CMEs can be formed regardless of the size of ARs.
We confirmed that the non-dimensional parameters using the information of flare ribbons, e.g., the ratios of magnetic flux on flare ribbon to the total magnetic flux over the AR (Toriumi et al. 2017, Lin et al. 2021) give larger AUC than the other parameters. These results suggest that the elucidation of what determines how the flare ribbon can expand is important to predict the occurrence of CMEs.
The objective of this paper is to investigate the various magnetic parameter to determine the formation of CME, focusing on the distribution of nonpotential magnetic field (BNP). To this end, not only parameters including the integrated parameters over whole active region (AR) but also the parameters focusing on the area satisfying BNP > 500G and BNP > 1000G are devised and evaluate how they well discriminate between the ARs producing eruptive flares associated with CME and confined flares not-associated with CME. To appraise their discrimination capability, I employ the receiver operating characteristic (ROC) curve and the area under curve (AUC). Moreover, I also calculate the AUC of the parameters proposed by the previous papers (Toriumi et al. 2017 and Lin et al. 2021) and compare their discrimination capabilities with our study.
In this study, the average magnetic flux density of AR (BAR), the average magnetic energy density of AR (ρAR) and some dimensionless quantities (called the λ-type and ω-type parameters) have high AUC (≧0.75). Especially, λ- and ω-type parameters used BNP of the area satisfying BNP > 500G perform well on AUC.
These results suggest that the area satisfying BNP > 500G is likely to be related to CME occurrence. Also, the fact that the parameters BAR and ρAR averaged over the AR are relatively better than the parameters given by the integration over the AR is consistent with the tendency that CMEs can be formed regardless of the size of ARs.
We confirmed that the non-dimensional parameters using the information of flare ribbons, e.g., the ratios of magnetic flux on flare ribbon to the total magnetic flux over the AR (Toriumi et al. 2017, Lin et al. 2021) give larger AUC than the other parameters. These results suggest that the elucidation of what determines how the flare ribbon can expand is important to predict the occurrence of CMEs.