| 其他摘要 | The Sun is the nearest star to earth, though an ordinary member of the star family in the cosmos. Because of this, the investigation of the Sun is very important for studying the formation, the evolution, the structure, and the outer atmosphere of the stars. More importantly, the third satellite of the Sun--the earth gives birth to wisdom of human beings. Moreover, the periodic activities of the Sun could threaten the living environment of the human being. The fierce activities, such as Flares, Coronal Mass Ejection (CME) and so on, could result in the perturbation of the magnetic field of the earth and ionosphere, the interrupt of the wireless transportation, the destroy of the power supply, the trouble of the space probes, the safety of the airman, the development of the space projection. Consequently, the investigation of the origin and the essence of the various activities is very important. This thesis is dedicated to the study of the sun, especially the exploration of the origin of solar activity by using a great deal of data obtained both by space and ground-based telescopes. It is structured as follow: In chapter one, on the base of surveying a number of references, we summarized the basic knowledge to sunspots and flares. In chapter two, we have investigated the M1.7 flare in active region NOAA 10424 on 2003 August 5 by using the data of TRACE, SOHO/MDI, BBSO, YOHKON/SXT. By observing the evolution of the active region, we found the sunspot with positive polarity rapidly rotating before the flare. This may indicate the way of the flare energy coming from the active region. It provides a good observational demonstration of the energy buildup, storage and release process in the corona for transient event. In chapter three, one flare of X3.4 in NOAA10930 and the flare X10 in NOAA10486 by using the data of Solar-b, MSFC, SOHO/MDI, YOHKOH/SXT. In the two active regions, we have found the the rapid rotation of the sunspot umbrae before the flares. Moreover, the transverse magnetic field were highly sheared with time and twisted magnetic loops were found in the corona. This study can provide more proofs to the mechanism of the flares. In chapter four, we have investigated the megnetic field evolution of the spiral sunspot by using the data obtained by Solar Spectrum Telescope mounted at Yunnan Astronomical Observatory. The study promote the knowledge about the importance of the motion of the magnetic field and magnetic field shear to the occurrence of flares. Finally, we describe the conclusion from the above studies and the future of our work. |
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