摘要
本文分析了南京大学太阳塔1991年10月24日用多波段光谱仪观测到的高时间分辨率（5s）的一个2N／X2．1级白光耀斑光谱．对耀斑谱线轮廓、连续发射强度、X射线和射电爆发资料进行了综合对比，分析表明，该耀斑属Ⅰ类白光耀斑，具有如下特征：（1）在白光耀斑的脉冲相期间，各波段光谱线心强度、连续辐射、谱线半宽以及线翼红不对称性与硬X射线高能波段的爆发同时达到极大；（2）H_a谱线在连续发射极大时半宽达10A，且呈现强烈的线心反转，H_β和H_γ线心亦有反转；（3）所拍摄的5条谱线都有明显的红不对称性，持续时间约为1分钟，根据上述结果，本文用电子束轰击、色球蒸发和色球压缩区对该耀斑能量积聚和释放的动力学机制作了定性的分析和解释。
In this paper, we analyse the spectra of a 2N/X2. 1 white-light flare (WLF) by comparing the line profiles and the continuum emission with X-ray and radio data. This WLF was simultaneously observed in five wavelength-bands with high temporal resolution (5s) on 1991 Oct. 24, by using the solar tower telescope of Nanjing University. Our measurement indicates that this flare was a Type I WLF and had the following characteristics: (1) during the impulsive phase, the continuum emission, line center intensities, full-half widths of the line profiles, red asymmetries at the line wings and the high energy X-ray emissiolls reach their maxima almost at the same time, (2) the H_α line was extremely broad (the full width at half-maximum of the line profile reached almost 10A) and showed strong central reversal when the continuum emission reached its maximum, which also appeared in H_β and H_γ lines,but was less strong, (3) all lines showed obvious red asymmetry at the wings. The duration was about one minute. Based on these results, we find that the theories of electron-beam bombardment, chromospheric evaporation and condensation can provide a good qualitative interpretation of the energy storage and release of this WLF.
基金
国家自然科学基金
