Cooperative Research of Solar Activity Based on Magnetic Shears

1991年成功发射的Yohkoh卫星仍在轨道上运行得相当好，并带来了许多新的成果。该卫星目前处于正常运行阶段。北大西洋天文台的耀斑望远镜和射电日像仪也开始了定期观测，并与希达圆顶太阳望远镜一起构成了一个全球地面太阳观测网络。1992年，Yohkoh和地面观测站之间的合作更加活跃。在此基础上，围绕Yohkoh数据的结果举办了几次研讨会和专题讨论会。1992年9月，以国内研究者为主要对象的“YOHKOH的一年研究”研讨会在NAO举行，1993年2月，第二届YOHKOH科学会议在NAO举行，来自国外的40多人参加了会议。他们两人都非常成功，并引发了很多讨论和未来的合作。这次太阳活动极大期的一个新的观测结果是建立了一幅起源于磁场重联和磁场剪切的太阳活动图象。对耀斑中磁重联释放能量和耀斑环中突然加热等离子体色球蒸发的现象进行了实际研究。日冕是动态的，活动区经常出现类似耀斑的短暂增亮、XBP强度的突然增加和等离子体的喷流状突变运动，冕洞在全球范围内改变了磁场结构，这一切都与日冕磁场重联过程密切相关。

The Yohkoh satellite, which was successfully launched in 1991, is still working quite well in orbit and bringing a lot of new results. The satellite is now in the regular-operation phase. The Flare Telescope and the Radio Heliograph in NAO also started their regular observations and constitute a global groundbased solar observation network, as well as the Hida Domeless Solar Telescope. The collaborations between Yohkoh and the observatories on the ground have been much activated in 1992. Based on this circumstance several workshops and symposia were held, centering the results from the Yohkoh data. In September 1992, the symposium "One Year Research of YOHKOH" was held at NAO mainly for domestic researchers and the second Yohkoh Science Meeting was held in February 1993, in which more than forty people participated from abroad. The both of them were quite successful and stimulated a lot of discussions and future collaborations. One of the new observational results in this solar activity maximum is that a picture of the solar activity has been established which originates from the magnetic reconnection and the magnetic shears. In solar flares, the scenes of the energy release via the magnetic reconnection and of the chromospheric evaporation of abruptly heated plasmas in the flaring loop were actually investigated. It has also revealed evident that the solar corona is quite dynamic, that a small flare-like transient brightening, a sudden increase of XBP intensity, and a jet-like abrupt motion of plasma are very common in active regions, that coronal holes globally change their structure of magnetic field and that all of them are closely related with the reconnection process of the magnetic field in the solar corona.