Quasi-periodicity Study Of Coronal Mass Ejections With Different Angular Width

Solar activity has a periodicity of 11 years and a mid-term quasi-periodicity between 27 days and 11 years.Coronal Mass Ejection(CME)is an important solar activity that affects the solar-terrestrial space environment,and the study of the midterm periodicity of CME is of great importance.the quasi-periodic variation of CME reflects the interrelationship between coronal magnetic activity,solar flare outbursts and interplanetary space oscillations.The angular width characterizes the size of the CME,which is an important physical parameter of the CME.In this paper,we use the CME data provided by SOHO/LASCO’s CDAW data catalog to classify and study the CMEs with different angular widths,mainly including:1.collecting and collating data of 31 310 CME events from January 1,1996 to August 31,2021,according to halo CME(angular width = 360°),partial halo CME(120°<angular width <360°),normal CME(20 degree <angular width ≤ 120°)and narrow CME(angular width ≤ 20°)for classification study;2.the behavior of physical properties(incidence,velocity,acceleration,latitude and mass)and the relationship between physical properties(angular width vs.velocity,angular width vs.acceleration,angular width vs.latitude and angular width vs.mass)for CMEs of different angular widths were studied;3.the quasi-periodicity of the incidence of CMEs with different angular widths was studied by using the fast Fourier transform and the continuous wavelet transform.The following results were obtained:1.most CMEs belong to normal CMEs and narrow CMEs,halo CMEs and partial halo CMEs are fast with negative acceleration,and normal CMEs and narrow CMEs are slow with positive acceleration.the CMEs are mainly distributed in low latitudes.The mean mass of partial halo CMEs is the largest,while the mean mass of narrow CMEs is the smallest.The incidence,velocity and latitude of various angular width types of CMEs exhibit an 11-year cycle.The angular widths of CMEs were more strongly correlated with velocity and mass than acceleration and latitude.2.The same cycles as those of existing studies were obtained: 1.2(±0.01)months(all CME,partial halo CME and normal CME),3.1(±0.04)months(all CME),6(±0.2)months(all CME,halo CME,partial halo CME,normal CME and narrow CME),7.3(±0.3)months(halo CME,narrow CME),8.5(±0.4)months(partial halo CME),10.8(±0.6)months(halo CME and narrow CME),1(±0.1)year(all CME,partial halo CME,normal CME and narrow CME)and 2.4(±0.4)years(all CME,normal CME and narrow CME).Some new cycles were obtained: 1.8(±0.02)months(halo CME),2.1(±0.1)months(halo CME),2.9(±0.04)months(narrow CME),1.4(±0.1)years(partial halo CME),1.7(±0.2)years(halo CME),2(±0.2)years(narrow CME),3.4(±0.7)years(halo CME and partial halo CME)and 4.1(±0.2)years(narrow CME).3.The periodicity of different angular width CMEs was not completely consistent.All angular width CMEs have periodicities of 11 years and 1.9 years,and all have a periodicity in the range of 0.8-3.3 months,4.1-6.5 months,and 1-1.3 years.A few have cycles of 9 months(partial halo CME,partial halo CME in the southern hemisphere,normal CME in the northern hemisphere,and narrow CME in the southern hemisphere)and 1.7 years(halo CME and narrow CME),as well as cycles in the range of 3.3-4.3 years(all types of CME are detectable except for normal CME,which is relatively rare),which may be related to the nature of the different angular width CMEs themselves.