Cooperative Research of Solar Activity Based on Magnetic Shears

1991年成功发射的Yohkoh卫星仍然在轨道上工作得很好，并带来了许多新的成果。该卫星目前处于正常运行阶段。NAO的耀斑望远镜和射电日像仪以及飞驒无罩太阳望远镜也开始了常规观测，构成了全球地面太阳观测网。Yohkoh与地面天文台之间的合作在1992年大大活跃起来。基于这种情况，围绕Yohkoh数据的结果举行了几次研讨会和专题讨论会。1992年9月，在北大举办了以国内研究人员为主的“YOHKOH一年研究”专题讨论会；1993年2月，举办了第二次YOHKOH科学会议，有40多名国外学者参加。他们都非常成功，并激发了许多讨论和未来的合作。这次太阳活动极大期的新观测结果之一是建立了一幅源于磁重联和磁剪切的太阳活动图。在太阳耀斑中，通过磁重联释放能量的场景和在耀斑环中突然加热的等离子体的色球蒸发的场景实际上进行了研究。研究还表明，太阳日冕具有很强的动动力，在活动区域，类似耀斑的短暂变亮、XBP强度的突然增加和类似喷流的等离子体的突然运动是非常常见的，日冕洞在全球范围内改变了它们的磁场结构，这些都与日冕磁场的重联过程密切相关。

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.