Analysis The Stability For The Large Scale Anisotropy Of Cosmic Ray With Yangbajing Experiment

A lot of experiments have detected the anisotropies of cosmic-rays with the magnitudes over one thousand of the level. While there are still some differences in their detail structures.The causes of the differences are still unknown, while studding them will help us to understand the cause of the cosmic ray origin and get more information about the structure of the interplanetary magnetic field.Because of the Yangbajing cosmic ray observatory’s advantages of high altitude and wide field, AS(?) accumulated a large amount of data, which allowing us can analyze the large-scale cosmic ray anisotropy. In my work, I used χ2 iterative method based on equal zenith to evaluate the background. The major work is about the dependency of cosmic rays on time or energy.From the result of years we found that, the amplitude of anisotropy is relatively stable and only increasing less than one per ten thousand. While the phases showed a cyclical change relating to the solar activity. By analyzing the anisotropy in seasons we find that there is a seasonal modulation in it. It may be caused by the influences of interplanetary magnetic as the earth revolution.Before reaching the earth, the cosmic rays pass through the magnetic field first. As the sun is the nearest source from our earth, its activity influenced the cosmic rays with low energy. At low energy range, the amplitude and phase of cosmic rays anisotropy have larger change with the passage of time than the high energy ranges. Moreover the phases of low energy anisotropies are gradually close to the high-energy cosmic rays with the time. This change is consistent with the solar cycle, that means the phases of low and high energy cosmic rays have larger difference in years when solar activity is intense, while become almost same in years when the solar activity are relatively calm. The cosmic rays with lower energy are more susceptible by the sun’s magnetic field, thus we speculate that the phases’ change of cosmic rays’ anisotropy is Associated with the solar activity.In order to explore the energy dependence of anisotropy, we put the data of AS(?)experiment into 4 parts to analyze. The results showing that at higher energy the relativeintensity of cosmic rays has a tendency of increase. Divide the sky into four areas according to the location of the exception structures and study them separately. We find that the relative intensity of A and C areas have a tendency of increase at first and then become weak with the increase of energy. While the relative intensities of B and D areas are more stable and have similar size. Thus we speculated that even though A-zone and B-zone’s locations are close while their physical mechanisms are different.This paper is structured as follows:The first chapter introduces the components and energy spectrum of cosmic rays, a few experiments that use different detect methods and the large-scale anisotropy of cosmic rays.The second chapter introduces the AS(?) and ARGO experiments and the analysis methods in this work.The third chapter introduces the temporal modulation of large-scale cosmic ray anisotropy. In dictating that cosmic rays are related to solar cycle and the anisotropic relative intensity has seasonal effect. From the changing of phases with low and high energy, we find the difference of phases with different energy is greater when the solar is more activity.The fourth chapter introduces the energy dependence of the large-scale anisotropy of cosmic rays.The fifth chapter summarizes the above works and contrasts the results of ARGO and AS(?) experiments and finally introduces the future work.