摘要
在文[11]工作的基础上,本文进一步用完全线性化方法和N-LTE理论半经验模型来计算1984年10月18日日珥的各种物理参数。经过分析得到如下结论: 一、在求日珥谱线的多普勒半宽Δλ_D时,完全线性化方法比经典的半宽法精度高。 二、本文应用文[9]的N-LTE计算程序计算了同日珥观测轮廓相符合的半经验模型,得到日珥电子温度T_e和氢原子密度n_H在日珥内的分布及钙元素的含量。结果得到,该日珥中心附近的温度约为5900K,温度从中心向表面增加;日珥内湍动速度为5.5～6.5公里/秒;氢原子的平均密度(?)_H=3.8×10^(11)cm^(-3)。日珥中钙元素主要由一次和二次电离钙组成,且n(CaⅢ)》n(CaⅡ)。 三、本文由观测的谱线辐射总能量求出氢原子柱密度按能级的分布,并将此结果与局部热动平衡(LTE)和非局部热动平衡(N-LTE)计算结果加以比较,得出:日珥中氢原子在较低能级处于N-LTE状态,在高能级接近LTE状态。
Spectral analysis is one of the main methods for studying solar prominences. Recently some new methods of spectral analysis have been proposed by several Chinese authors. In this paper, we use some of them, i.e. the complete linearization method and the N-LTE mode, to analyze the spectral data of a large and quiescent prominence on Oct. 18, 1984. The spectra were observed by one of the authors (Ye Shihui) with the spectrograph at Norikura coronal station of Tokyo Astronomical Observatory in Japan. The profiles of 45 emission lines including Balmer lines of hydrogen and metallic lines have been treated in an earlier paper [11] .The main conclusions are as follows:1. The Doppler width ΔλD of the prominence spectral lines obtained by the complete linearization method is smaller than that derived from the classical HW method, because in the later case the second order-term of the optical depth (τλ ) is ignored.2. Using N-LTE theory to calculate the semi-empirical model of the prominence, which reproduced well the observed profiles, we have derived the distributions of the electron temperature and the number density of hydrogen atoms in the prominence. The temperature near the center of the prominence was found to be about 5900K, and increased from the center to the surface. The turbulence velocity of the prominence was about 5.5-6.5km/s. The average density of hydrogen atoms was 3.8 f66 1011cm-3, In addition, it is found that calcium atoms appeared mainly in the forms of Call and CaⅢ and n(CaⅢ) > n(CaⅢ). Therefore, if one wants to calculate the number densities of calcium and hydrogen atoms by means of CaⅡ K, H lines, the contribution from CaⅢ must be considered.3. The distribution of the column densities of hydrogen atoms (Ni) at the energy levels above i= 10 or 11 derived from the observed total radiative energy in the lines (E'λ) is consistent with that deduced from the Boltzmann formula. This means that the atoms of hydrogen at higher energy levels are in LTE. On the contrary, the values of N5, N7 and N8 derived from E'λ. are basically consistent with the results obtained from N-LTE semi-empirical modeling. This indicates that the atoms of hydrogen at lower energy levels are in N-LTE.
基金
国家自然科学基金
国家教委博士点基金
关键词
日珥
光谱分析
太阳
Sun (the): prominences-Spectral analysis
