一类偶发物质抛射事件的观测和数值模拟物理解释

Application of no Fiducial Approach in SLR Data Processing

研究了2000年紫金山天文台赣榆观测站观测到的在太阳上7个中小抛射事件,认为它们的特点是不伴随发亮现象,长1—2.5万公里,宽3—5千公里,寿命3—7分钟,产生在弱磁场处远离大黑子的地方。用一维沿磁弧流动的流体力学方程的数值模拟来解释这种抛射,结果显示,与Suematsu等和Shibata等模拟计状物和日浪不同,不是激波或反弹激波将光球色球密度量级的物质推向日冕,而是重联后的连续物质流动形成这类抛射的,大约5分钟的演化,即可达到流体力学稳定解。

In this paper, we introduce the observations, which were made at Ganyu Solar Station of Purple Mountain Observatory, of 7 mass ejection events. What characterizes these events is that they are often produced in the weak magnetic region and they are not accompanied by brightening. Their usual lifetime is 3-7 minutes and their usual size is 10000-25000km long and 3000-5000km wide. We use ID numerical simulation of flows along magnetic field to explain this kind of phenomena. Our result is different from that of Suematsu et al. and Shibata et al., who simulated spicules and surges and regarded the mass ejections as a result of shock wave pushing effects. We think they are due to continuous mass flows along magnetic field after magnetic reconnection in the lower chromosphere. The simulation shows that a steady hydrodynamic flow can be achieved after 5 minutes' evolution.