1986年2月4日太阳耀斑的演化研究

本文根据乌鲁木齐天文站的H_α耀斑及3.2cm射电流量观侧资料、云南天文台的黑子精细结构照相和Marshall Space Flight Center的向量磁场图,对1986年2月4日的六个耀斑的形态相关及演化联系,特别是0736UT 4B/3X大耀斑的发展过程进行了综合分析。主要结果是: 1.4日大耀斑的初始亮点和闪光相的主要形态演化,与活动区中沿中性线新浮现的强大电流/磁环系密切相关。后者的主要标志是沿中性线的长的剪切半影纤维及它两端的偶极旋涡黑子群(1_3F_3)。 2.上述大耀斑与1972年8月4日0624 UT大耀斑爆发的磁场背景及主要形态特征相似,表明两者的储能和触发机制可能相同。 3.大耀斑爆发的H_α初始亮点,双带出现,环系形成,亮物质抛射和吸收冕珥等现象同3.2cm射电流量的变化在时间上有较好的对应关系。 4.重复性的前期小耀斑爆发位置和发展趋势与大耀斑的主要形态及演化特征相似。它们相对于剪切的纵场中性线两侧的位置相近或相同。因而,可以看作上述强大电流/磁环系不稳性发展过程中的前置小爆发。

The Evolution of Flares on 4 February 1986

Based on the data of Ha and 3.2cm radio flux patrol observed at Urumqi Astronomical Station, the vector magnetic fields (VMF) at Marshall Space Flight Center and the sunspot photograms at Yunnan Observatory, the morphological evolutions of the major flare 4B/3X at 0736UT and the preflare-activities in active region AR4711 on 4 February 1986 are analysed in the paper. The main results are:1.The locations of initial brightening and the characteristics of morphological evolution of the major flare on 4 Feb., 1986 have a close correlation to the newly emerging electric current/magnetic loop system flowing along the northsouth neutral (H11 = 0) line. It was marked by a longer and sheared penumbral filament system linking to a bipolar with spiral patterns (L3 and F3) at its both ends.2. The distribution of the photospheric magnetic fields (N- and S-polarities) and their motions, the orietation of sheared penumbral filaments along the north-south neutral line, and initial brightening and their evolution of the major flare in AR4711 were all very similar to the flare in the famous region McMath 11976 on 4th August, 1972. This means that the building-up of the flare energy, trigger mechanism and the energy release could be the same for the two flares.3. During the major flare, the two-ribbon appearance, loop system formation, mass ejections and their flows back to the chromosphere had a good correspondance in time to the peaks of the 3.2 cm radio flux curve.4. Four preflares with about one-hour period and the initial brightening of the major flare were usually located at the footpoints of the strong current/magnetic loop system identified by Hagyard et al. (1988). Therefore, the preflares could be considered preludes of the largest explosion of the current system.