| At first, the author statistically analyzed the ratio of the number of CME withinthe angular width of0~60°,61~120°,121~180°,181~240°,241~300°,301~359oand360°representing the total number of CME, the comparison of CME withdifferent angular widths and the phase of the number of sunspots, the distribution ofCME in different angular widths in a solar cycle, CME’s velocity distribution andother features. We obtained the following:1. CME within the angular width of0~60°,61~120°,121~180°,181~240°,241~300°,301~359oand360°accounted for71.04%,20.06%,4.38%,1.12%,0.39%,0.04%and2.83%of the total respectively.2. The distribution of the number of CME within the angular width of0~60°overtime has three peaks (the first peak occurs at2000, the second peak appeared in2002, the third peak at2007). The distribution of the number of CME within theangular width of121~180°over time has only one peak (in2001). Number offull-halo CME distribution over time has two distinct peaks (the first peakappeared in2001, the second peak appeared in2005).3. The smoothed monthly mean CME numbers within different angular width isdifferent in time with the peak of the smoothed monthly mean sunspot numbers,usually there is some delay, whose length has something to do with CME angularwidth.4. The speed of CME varies with the change of solar activity. The average of themaximum speed of CME is later than the peak of the solar activity. At lowactivity years, the speed of CME with wide angular width and small angularwidth is almost the same, there is no obvious reflect of characteristics that thegreater the speed the greater the angular width, but near solar maximum years, thevelocity of large angular width is significantly higher than that of small angularwidth CME.5. As the speed increases, the proportion of CME within the angular width of0~60°decreases. The proportion of CME within angular width higher than120°isgradually increasing. Bellow the speed of1000km/s, the proportion of CMEwithin the angular width of61~120°is almost unchanged. Above the speed of 1000km/s, the proportion of CME within the angular width of61~120°declinesslightly.Secondly, we conducted a statistical analysis to the CME and Halo CME that arefaster than1000km/s. The results showed that70.4%of the CME whose speed isgreater than1000km/s is associated with flares eruption. The average speed of theCME accompanied with flare eruption is higher than those without flare eruption. Thesource regions of the CME and Halo CME accompanying the flare eruption whosespeed is greater than1000km/s are mainly distributed within latitude30°or less. Thespeed reaches its maximum around latitude15oand at the equatorial and high latitudesthe speed is relatively small. Halo CME mostly occurs near the center of the sun. Asthe longitude increases, the number of occurrences decreases, however, at the place oflongitude90°the number increases slightly. At initial stage of increased solar activitycycle, Halo CME latitude distribution range is above latitude20°of the northern andsouthern hemispheres. In solar maximum, CME mainly happens in the low latitudes.Thirdly and the last, by using the GS reconstruction method, with data obtained froma single satellite, we established the HT reference system, solved the GS equation,found the correct axial of the magnetic cloud and got two-dimensional map of themagnetic cloud by using the numerical solution of the GS function. We reconstructedall magnetic clouds in the solar cycle23that caused large geomagnetic storms. Then,we analyzed each magnetic cloud the by the way it got through the Earth, its magneticfield, helicity and other features. We found the initial characteristics of each magneticcloud corresponding to the CME. These features include: angular width, speed,location of the outbreak and other information. The results showed that the longituderange of the source region of the CME whose magnetic cloud center passes the Earth’sis E20°≤Longitude≤W35o. The longitude range of the source region of the CMEwhose edge got through the Earth’s is E15o≤Longitude≤W60°. The way that theregion between the center and the edge of the magnetic cloud pass the Earth we calledthe geomagnetic cloud transition zone that passes the earth. The longitude range of thesource regions that the transition zone passes the Earth is E35o≤Longitude≤W35o.The analysis also showed that for the majority of the events result in a largegeomagnetic storm which can be reconstructed as magnetic cloud, most of thegeomagnetic storms are generated by the magnetic cloud, for a few cases it is Sheath.These ICME’s corresponding CME are almost all Halo CME. |
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