The Research Of X-class Solar Flare And Related Phenomena

In this paper, we present a statistical on large soft X-ray flares of solar cycle21,22and23(from1986-2008). Statistical analysis results are as follows:1. It is found that the number of the X1-class flares, X2-class flares, X3&4-class flares, X5-to-X9-class flares and X10-and-above-class flares accounted for52.71%,20.59%,13.57%,8.37%and4.75%as a proportion of total X-class flares. Meanwhile,32.2%,31.9%,43.3%,81.08%and95.2%separately of them are produced by super activity regions. In solar cycle22, X-class flares are concentrated on the peak, while it is dispersive in cycle23.2. There are58flares equal to or greater than X5-class during solar cycle21、22and23. Most of them are mainly focus on three longitude zone:70°-110°,131°-199°,200°-260°and281°-360°. About91.4%of them are in the descending phase of the cycles.There is an obviously North-South asymmetry in cycle23, and an obviously East-West asymmetry in cycle21.3. The result shows that the smoothed-monthly mean of X1-class flares have a very noticeable time lead of1month in cycle21and cycle22respectively with respect to the smoothed-monthly mean sunspots numbers while a13months lag in cycle23. Moreover, for the X2-class and above flares, there is a time lag of9months in cycle21, a one-month time lead in cycle22and a time lag of32months in cycle23.We also present a statistical on solar proton events of solar cycle21,22and23(from1986-2008). Statistical analysis results are as follows:1. No matter to2-clas proton events or to3-class proton events, most of them occur in the descending phase of a solar cycle.The weaker of a solar cycle and the stronger class of proton events, the more proton events occur during the descending phase of the cycle. The phenomenon of proton events concentrated on the peak in cycle22, is outstanding. In cycle22, the source region of some events distribute higher than30°f the northern hemisphere.2. The source region of Ground Level Enhancement(GLE) events, which growth rate more than100%,is from W25°to W90°. While to the other proton events, those who has great growth rate are fouse on longitude zone from E30°to W20°.3. To2-or-above-class proton events, there might be1or2or3peaks. In cycle23, both the2-class events and3-and-above-class events have3peaks, meanwhile the largest peak appears after the peaks of solar the cycle.