本論文用STEREO(Solar Terrestrial Relations Observatory)太空船上的SECCHI(Sun Earth Connection Coronal and Heliospheric Investigation)儀器研究2008年3月25日及12月12日兩個日冕物質拋射事件，第一個事件伴隨強度M1.7級的閃焰，最高加速度距太陽表面0.55太陽半徑處，強度達1020.8 m/s2；第二個事件則是在日珥爆發後發生，距太陽表面1.98太陽半徑處，最高加速度達28.9 m/s2。兩事件在傳播過程中在速度上有明顯不同的性質，第一個事件起始速度快速增加但隨著距離的增加，速度逐漸下降，第二個事件起始速度低但隨著距離的增加，速度逐漸上升，造成如此不同的運動型態有可能是在傳播時受到太陽風的影響。伴隨閃焰事件加速度增加行為與軟X光射線通量微分值在時間的尺度上具有一致的關係。分別用等加速度及變加速度的冪次多項式擬合日冕物質拋射高度，結果顯示以變加速度的冪次多項式優於等加速度的冪次多項式，表示這兩個事件的加速度具有時變性質。 The objective of this work is to study the kinematic properties of two coronal mass ejections (CMEs) detected on 2008 March 25 and December 12 respectively by the SECCHI (Sun Earth Connection Coronal and Heliospheric Investigation) on-board STEREO (Solar Terrestrial Relations Observatory) spacecraft. The first CME was associated with an M1.7 class solar flare. Its highest acceleration occurred at about 0.55 R? from the solar surface with a magnitude of 1020.8 m/s2. The second event broke out after a prominence eruption. Its maximum acceleration occurred at about 1.98 R? from the solar surface with a magnitude of 28.9 m/s2. The kinematics profiles of the two CMEs are different. The velocity of the first event rises rapidly during the initial phase and then decreases afterward, while the velocity of the second one increases monotonically. The cause of the difference may be due to the effect of solar wind. The peak acceleration of the first event coincided with the peak of the derivative of the soft X-ray flux. The CME heights were fitted by the polynomials derived from constant and variable acceleration, respectively. The fitting results show that the “variable acceleration” polynomial fits both events better than the “constant acceleration” polynomial does. This means that the accelerations of both CMEs are time-varying.
