arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1705.02475astro-ph.SR
收藏

日珥中的Na I和Sr II共振线

The Na I and Sr II Resonance Lines in Solar Prominences

Goetz Stellmacher, Eberhard Wiehr

摘要:

我们估计的电子密度,n_e,和它的空间变化,从观察到的发射比的共振线Na I 5890(D2)和Sr II 4078在静态双折射。对于明亮的日珥(τ_α ~ 25),我们得到连续两天的平均n_e ~ 2*10^10 /cm ^3;对于暗淡的日珥(τ_α ~ 4),n_e ~ 4*10^10 /cm ^3,具有中等的内部波动,并且没有随太阳边缘以上高度的系统变化。从NaI/SrII的发射比推导出n_e所需的对谱线展宽的热和非热贡献T_kin和V_nth不能从观察到的不同质量原子的谱线宽度明确地确定。假设T_kin和V_nth相同,Sr II 4078的减小宽度Δ-λ_D /Δ_0显示出超过来自NaD 2和H-δ的减小宽度。我们把这种过度的展宽归因于离子与日珥磁场的相互作用引起的更高的非热展宽。这是由发现SrII 4078的宏观位移高于NaD 2的宏观位移所暗示的。

英文摘要:

We estimate the electron density, n_e, and its spatial variation in quiescent prominences from the observed emission ratio of the resonance lines Na I 5890 (D2) and Sr II 4078. For a bright prominence (tau_alpha ~ 25) we obtain a mean n_e ~ 2*10^10 /cm^3; for a faint one (tau_alpha ~ 4) n_e ~ 4*10^10 /cm^3 on two consecutive days with moderate internal fluctuation and no systematic variation with height above the solar limb. The thermal and non-thermal contributions to the line broadening, T_kin and V_nth, required to deduce n_e from the emission ratio NaI/SrII cannot be unambiguously determined from observed widths of lines from atoms of different mass. The reduced widths, Delta-lambda_D / lambda_0, of Sr II 4078 show an excess over those from NaD2 and H-delta, assuming the same T_kin and V_nth. We attribute this excess broadening to higher non-thermal broadening induced by interaction of ions with the prominence magnetic field. This is suggested by the finding of higher macro-shifts of SrII4078 as compared to those from NaD2.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑