太阳耀斑(后)环系物理量的二维分布和演化特征  

Two-dimensional Distributions and their Evolutions of Physical Quantities for a Post-flare Loop System

作　　者：顾啸马[1] 钟树华[1] 敦金平[1] 

机构地区：[1]中国科学院国家天文台云南天文台,云南昆明650011

出　　处：《天文研究与技术》2004年第1期47-55,共9页Astronomical Research & Technology

摘　　要：用"多云模型"方法对1989年8月17日太阳边缘耀斑的二维Hβ光谱进行分析研究,得到了该耀斑环系3个物理量(氢原子在第二能态的柱数密度N2,激发温度Tex和微湍流速度Vt)在不同时间的二维分布和演化特征,结果表明:(1)密度,温度和湍流速度的分布是不均匀和不对称的,它们的分布跟耀斑环内的位置密切相关、而与高度关系不大;(2)密度N2和湍流速度Vt随时间减小,而温度几乎不变,环顶温度还随时间有所增加;(3)首次揭示了N2和Tex的极值位置从环的一个腿向环的顶部移动,而同时Vt的极值位置却由环顶部向环的另一个腿运动,似乎在环内形成类"虹吸"现象。The 2D H_β spectral data of the post-flare loop system (PFLs) of August 17, 1989 are obtained and analyzed quantitatively for three different times. Three physical quantities (i.e., the column number density of hydrogen atoms at the second level along the line-of-sight direction N_2, the excitation temperature T_(ex) and micro-turbulence velocity V_t) and their 2D fields are derived during the three times.The time variations of the 2D field are given for the three quantities more than one hour after the maximum of the Hα flare. Our analyses show that the average values of N_2 and V_t decrease with time, while T_(ex) is nearly unchanged except for the top part of the PFLs where it is increasing slightly with time. The distributions of N_2, T_(ex) and V_t are inhomogeneous and asymmetric in the PFLs, they have a close relation with the position within the PFLs, but a little relation with the height above photosphere.A new evolution property is found in which the regions with the maxima of T_(ex) and N_2 move from the middle of the southern leg towards the top part of the PFLs, while the position of V_t maximum shifts from the top part towards the northern leg of the system to form a 'siphon'-like phenomenon. This scenario may be a result of successive formation of new loops at higher heights while under continuous cooling.

关 键 词：太阳耀斑 环系物理量 分布 时间演化 二维Hβ光谱 

分 类 号：P182.52[天文地球—天文学]