日冕瞬变的观测特征和理论解释

本文综述了日冕瞬变现象的主要观测特征及其理论模型.日冕瞬变是从太阳日冕中向行星际空间大量抛出物质的过程,每次事件可有5×1015克的物质在103秒的时间内以约500公里/秒的典型速度被驱动流到日球中.日冕瞬变与太阳耀斑和爆发日珥事件有密切的相关性.作为一种新的太阳活动现象,近年来对日冕瞬变提出了许多理论解释.一种数值模拟方法将瞬变看成是由于热力学量或磁力在日冕底部的脉冲增长所产生的结果.许多分析模型认为是由磁环内部的电磁力或外部的磁压力驱动所致,或者是环中磁浮力驱动的结果.考虑到瞬变与耀斑和爆发日珥的相关性,活塞驱动模型认为,瞬变是稠密等离子体喷射,像活塞驱动机制.观测和理论都有待于进一步的研究. 

The Observational Features and Theoretical Explanations of the Coronal Transients

The major observational features and theoretical models of the coronal transients are reviewed in the present paper. The coronal transient is the process with a large amount of mass ejection from the solar corona into the interplanetary space. There is 5×1015 grams of mass which is driven into the heliosphere with the typical velocity 500 km/sec in the period of 103 seconds. There are close connections between the coronal transients and the events of solar flare and eruptive prominence. As a recent discovered phenomenon of the solar activity, many theoretical explanations have suggested for the coronal transient processes in the recent years. One approach is the numerical similarity, in which the coronal transient is driven by the pulsation of one of the thermodynamical quantities or the magnetic pressure at the low corona. Several analytical models consider that the loop transient is driven by the Lorentz force in the loop, or by the magnetic pressure outside the loop, or the MHD buoyancy force of the loop. By consideration of the connection between the transient and the solar flare and eruptive prominence, piston driving model suggest that the coronal transient is driven by the ejection of the dense plasma. More researches should be completed in both the observations snd the theories in future.