太阳黑子半影的形成和返回磁通量的来源

THE FORMATION OF SUNSPOT PENUMBRAL MAGNETIC FIELD AND THE ORIGIN OF RETURN FLUX

本文从无半影的黑子成长为带半影的黑子伴随着磁场强度增强和延伸运动这个观测事实出发，通过MHD数值模拟，证明了：（1）对流层内黑子中涡旋流动的自然形成；（2）仅在黑子表面附近磁矢才急速向外移动，最终形成我们观测到的半影磁场位形；（3）光球之上由于β迅速减少，这么小的延伸速度（0.2公里／秒）仅在β～1的光球区200公里厚的层里使磁矢有效地旋转，在约几小时至一天量级时间内将近似垂直的本影磁场向水平方向旋转，形成Osherovich所期的ReturnFlux磁位形，将注入日冕空间的本影主磁流同在色球和光球内就返回的半影磁流自然地划分开来．

Some numerical simulations of the process of sunspot formation are made in this paper.The main results of computations are as follows: (1) The eddy flow that Meyer used to establish his model of sunspots is naturally formed in our simulation.(2) Ohly in the upper convective layer near the photosphere, magnetic fields move out quickly and eventually the penumbral magnetic configuration is formed.(3) Abovethe sunspot surface, due to the fast decrease of the plasma β-ratio, such extending movement with a speed of 0.2 km /s rolls the field vector only within the layer about 200 kin thick below the chlomosphere.As a result, the total magnetic flux is divided into two parts. One is the main part going up into the corona, and the other is Osherovich's return flux that carmot reach the corona.