Latitude Distribution Characteristics Of Coronal Mass Ejection

Coronal Mass Ejection(CME)is a violent eruption of plasma and magnetic fields in the solar atmosphere,which is an important component of solar activity.Because CME is closely related to the solar-terrestrial space environment,it is of crucial importance to study in depth.To explore the temporal and spatial behaviours of CME in depth,this paper investigates the correlation and phase of the occurrence rate of CME at different latitudes with the low coronal index(10.7 cm Radio Flux,F10.7)and high coronal index(Coronal Brightness Index,CBI),respectively,using CME data with complete23 and 24 solar cycles from the CDAW catalogue of SOHO/LASCO relationships.Meanwhile,the behaviour of the physical parameters(speed,acceleration,angular width,mass and kinetic energy)and the relationships between the physical parameters(speed and acceleration,speed and angular width,speed and mass,and mass and angular width)of CME at different latitudes are investigated in detail in order to gain a more comprehensive understanding of the dynamics of CME at different latitudes.The results of our study indicate that:(1)The occurrence rate of the high-latitude CME correlates more strongly with the high-latitude CBI.In contrast,the occurrence rate of the low-latitude CME is more correlated with the F10.7.Therefore,we could speculate that the source regions of high/low-latitude CME may vary in height: the source regions of highlatitude CME are closer to high coronas,and the source regions of low-latitude CME are closer to low coronas.(2)There is a relatively stronger correlation relationship between CME,the F10.7,and the CBI for solar cycle 24 than solar cycle 23.The difference in the correlation degree during different cycles might be associated with the real differences in the behaviors of strong and weak photospheric magnetic fields in cycles 23 and 24,(3)For solar cycle 23,the high-latitude CME occurrence rate lags behind the F10.7by 3 months,whereas for solar cycle 24,they are in phase.For solar cycle 24,the low-latitude CME occurrence rate leads the low-latitude CBI by 1 month,whereas for solar cycle 23,they are in phase.The high solar coronal index(CBI)lags behind the low solar coronal index(F10.7)by approximately 2 months in phase.To some extent,our results support the due to the upward evolution of solar activities,the cycles of upper activity indices commonly lag behind the lower activity indices by several months.At the same time,our results also support that the phase relationships between solar activity indices may also be influenced by different solar activity weeks.(4)There are similarities and differences in the evolutionary characteristics of physical parameters between high and low latitude CME.Their physical parameters largely obey a log-normal distribution,except for acceleration.Statistical averages show that at 23 solar cycles,low-latitude CME have faster speeds,smaller accelerations,smaller angular widths and smaller masses compared to high-latitude CME,but equal kinetic energies.At solar cycle 24,low-latitude CME have slower speeds,lower accelerations,larger angular widths,smaller masses,and lower kinetic energies compared to high-latitude CME.(5)The linear slopes of speed vs.angular width,speed vs.mass,and mass vs.angular width are greater for low-latitude CME compared to high-latitude CME.The research in this paper sheds further light on the latitudinal distribution characteristics of CME,providing important clues to a deeper understanding of their origin and evolution,and helping to further explore the nature of solar activity.