本文選題：太陽光球 + 磁亮點��； 參考：《中國科學院研究生院（云南天文臺）》2013年碩士論文

【摘要】：在太陽光球表面出現(xiàn)的磁亮點是目前的觀測手段能夠分辨的最小磁結(jié)構(gòu)，也被認為是日冕磁場在光球的足點運動的可靠的示蹤者，其運動所耗散的能量被認為是日冕加熱和色球加熱的最終能量來源之一。在其運動過程中，高密度的光球物質(zhì)帶著磁場一起運動，在色球和日冕磁場當中產(chǎn)生波動或者扭絞將光球物質(zhì)的動能傳送到色球和日冕。為了解開日冕加熱和色球加熱等世紀未解之謎，對磁亮點的研究就顯示出了它特殊的重要性。關于磁亮點的形成原理，很多科學家都認為是在磁通量管的對流塌縮過程中形成的。也有很多觀測方面和數(shù)值模擬方面的研究結(jié)果重現(xiàn)了對流塌縮過程，確認了磁亮點確實是在對流塌縮過程中形成的。即對流塌縮的過程是先有強的等離子體流下沉，磁場強度增強，，最后磁亮點出現(xiàn)。一些數(shù)值模擬和觀測的結(jié)果發(fā)現(xiàn)，在對流塌縮過程中，當強的等離子體流下沉到密度較大的磁通量管底部時會發(fā)生較強的反彈上升現(xiàn)象。而這個上升的等離子體流會形成激波上升至日冕形成針狀體。與此同時，在磁通量管底部的等離子體反彈上升的過程中，磁通量管溫度上升，磁場強度減小，最后導致磁通量管破裂。這是磁通量管的另一種不穩(wěn)定性。理論研究發(fā)現(xiàn)，當磁環(huán)在光球上的足點以1-2km s~(-1)運動時，足點所在的磁通量管產(chǎn)生振蕩并激發(fā)阿爾芬波。阿爾芬波在光球中被激發(fā)，然后向上傳播到色球和日冕層，并在色球和日冕層中消耗掉能量以加熱色球和日冕。不過，阿爾芬波還沒有在光球?qū)訖z測出來。光球上的足點是否有1-2km s~(-1)大小的運動速度是研究光球磁通量管能否通過振蕩產(chǎn)生阿爾芬波的一個關鍵因素。磁亮點的尺度在100-200公里之間，磁亮點的亮度是光球平均亮度的2-4倍。磁亮點的運動速度平均在1-2公里/秒。也有少數(shù)磁亮點運動速度較快，達到3-4公里/秒。研究發(fā)現(xiàn)有一些磁亮點沿著對數(shù)螺線方式進行渦旋運動。磁亮點的壽命從幾十秒到幾十分鐘不等。亮度較大，尺度較大的磁亮點的壽命較長。對磁亮點的研究基于準確的識別方法。我們運用區(qū)域生長法對磁亮點進行識別，并給出了識別的結(jié)果。
[Abstract]:The magnetic bright spot on the surface of the solar sphere is the least magnetic structure that can be distinguished by current observation methods, and is also considered to be a reliable tracer of the coronal magnetic field moving at the foot of the photosphere. The energy dissipated by its motion is considered to be one of the final sources of energy for coronal heating and chromosphere heating. In the course of its motion, the high-density light-ball material moves with a magnetic field and waves in the chromosphere and the coronal magnetic field, or twists the kinetic energy of the light-ball matter to the chromosphere and the corona. In order to solve the unsolved mystery of coronal heating and chromosphere heating, the study of magnetic highlights shows its special importance. Many scientists believe that the formation of magnetic bright spots is due to the convection collapse of magnetic flux tubes. There are also many observations and numerical simulation results to reproduce the convection collapse process, which confirms that the magnetic bright spot is really formed in the convection collapse process. The process of convection collapse is that there is a strong plasma flow sinking, the magnetic field intensity is enhanced, and finally the magnetic bright spot appears. Some numerical simulations and observations show that a strong rebound and rise will occur when a strong plasma flows down to the bottom of a dense magnetic flux tube during convection collapse. This rising plasma stream forms shock waves that rise to the corona to form acicular bodies. At the same time, in the process of plasma rebound and rising at the bottom of the flux tube, the temperature of the flux tube increases and the magnetic field intensity decreases, which finally leads to the rupture of the flux tube. This is another instability of the flux tube. Theoretically, it is found that the flux tube in which the magnetic foot is located oscillates and excites the Alfen wave when the step of the magnetic ring moves in the 1-2km squi-1). Alfven wave is excited in the sphere of light and then propagates upward to the chromosphere and the coronal layer and consumes energy in the chromosphere and coronal layer to heat the chromosphere and corona. However, Alfven wave has not been detected in the photosphere. It is a key factor to study whether the spheroidal flux tube can produce the Alfen wave by oscillating or not. The magnetic bright spots range from 100 km to 200 km, and the brightness of the magnetic bright spots is 2-4 times that of the average luminous sphere. The average velocity of the magnetic spot is 1-2 km / s. There are also a few magnetic highlights moving faster, up to 3-4 km / s. It is found that there are some magnetic highlights moving along the logarithmic spiral. Magnetic highlights range in life from tens of seconds to tens of minutes. The lifetime of magnetic bright spots with higher brightness and larger scale is longer. The study of magnetic highlights is based on accurate recognition methods. The region growth method is used to identify the magnetic highlights, and the recognition results are given.
【學位授予單位】：中國科學院研究生院（云南天文臺）
【學位級別】：碩士
【學位授予年份】：2013
【分類號】：P182.4

【參考文獻】

相關期刊論文 前1條

1 李東;寧宗軍;;太陽大氣中的光球亮點[J];天文學進展;2012年02期

本文編號：1826007