Study Of The Kinematics Of Coronal Mass Ejections In The Solar Atmosphere

Corona Mass Ejection (CME) is one of the intense eruptions in the solar atmosphere and it is the activity which has the closest relationship with the space weather events. CME is the main source of the intense geomagnetic storms and the solar energetic particles. The CME's velocity may affect its ability to drive a shock and change the CME's arrival time, while the propagation direction would determine whether or not a CME can arrive at Earth. So, the study of CME's kinematic characteristics in the solar atmosphere is important for understanding the space weather effect of CMEs and improving the space weather forecast. Based on the STEREO observation and the Graduated Cylindrical Shell model (GCS) which developed by Thernisicn et al. [2006,2009], the kinematics of CMEs are studied.The STEREO firstly provides the chance to reconstruct the 3-Dimensional information of CMEs from the observations of the Sun from dual vantage points. By studying two typical CME events which erupted on April 9 2008 and December 12 2008, we introduced the application of the GCS model in reconstructing the 3-dimensional information of CMEs, and discussed the errors. Further, we analyzed the 3-dimensional velocity of CME. By comparing the corrected results given by two different methods of projection-effect correction (the two different methods are the simple one used by Shen et al. [2007] and the complicated one proposed by Leblanc et al. [2001]) with the 3-Dimensional results derived by the GCS model, we found two different methods of projection-effect correction both have some limitations in the kinetic discussion of CMEs. Besides, we gave the applicabilities of the two different methods of projection-effect correction. Twenty-one well-structured CMEs were studied based on STEREO-SECCHI observations during 2007-2008. We have compared the projected velocity and the corrected velocities derived from the STA and STB, respectively, with the 3-dimensional velocity derived from the GCS model. It is found that:(1) For the simple method, the difference between the 3D velocity and the corrected velocity is smaller than 10% when the angular distance is greater than 50 degree. When the angular distance is less than 50 degree, the difference is obvious and it could as big as 90%. (2) For the complicated method, the difference between the 3D velocity and the modified velocity is smaller than 10% when the angular distance is greater than 45 degree. But, even if the angular distance is very small, the difference between them will not exceed 20%. So, the complicated method has a stronger applicability. We also found that the difference between the projected velocity and the 3D velocity is smaller than 10% when the angular distance is greater than 65 degree. It is implies that the projected velocity or height of limb CMEs does not need to be corrected. The results also help us understanding the corrected velocity better when only one vantage point observation cloud be used.Based on the above work, we systematically studied the deflected propagation of CME in the Solar atmosphere. Firstly, we studied the kinematic evolution in the meridian plane of the 8 October 2007 CME which could be treated as a limb event based on the STEREO B observation. The observational result shows that this CME obviously deflected to the low latitude region by 30°at the beginning. After this, the CME propagated radially. By analyzing the distribution of magnetic energy density, we found that the deflection of this CME at early stage was under control of the background magnetic energy density gradient and that the CME tended to propagate to the region with lower magnetic-energy density. Based on the analysis, we suggested for the first quantitative theoretical model which could describe the CME's deflected propagation:the Mganetic Energy Density Gradient (MEDG) model.Further, by the dual vantage points observations of STEREO and the GCS model, the statistical characteristic of the deflections of ten CMEs which occurred from November 2007 to the end of 2008 were studied. Eight of these CMEs are found to be deflected during its propagation in the corona. The deflection not only occurred in latitude but also in longitude. The distribution of the coronal magnetic field extrapolated from the SOHO/MDI magnetic synoptic charts suggests that the CMEs tend to deflect to the region with lower magnetic energy density. The further quantitative analysis reveals that the CMEs have higher deflection rates in the inner corona, generally below 4 Rs. The directions of the deflection and the gradients have a good consistency. There is a positive correlation with the correlation coefficient of 0.85 between the CME deflection rate and the strength of the magnetic energy density gradient. A stronger gradient may cause a larger deflection rate. Meanwhile, the CME speed has a negative effect on the deflection rate. The correlation coefficient is-0.6. A faster event tends to have a slower deflection rate. The statistical results further confirm the deflected propagation of CMEs in the Corona could be quantitatively described by the Mganetic Energy Density Gradient (MEDG) model which will be helpful for us to establish the whole forecasting model of the CME's geoeffcctiveness...