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arXiv 1303.1126astro-ph.SR
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日珥的空间和地面同步光谱观测

Spectroscopy of Solar Prominences Simultaneously from Space and Ground

G. Stellmacher, E. Wiehr, I. E. Dammasch

摘要:

我们提出了一套全面的光谱数据,从两个静态的太阳能平行观察从空间和地面:与VTT,同时二维成像的H-β 4862和钙II 8542产生一个恒定的比例,表明小的空间压力变化的太阳能。用Gregory同时获得了Ca Ⅱ 8542和He Ⅰ 10830的光谱,其宽度为8000< T_kin< 9000 K,v_nth<8 km/s。氦三重态分量的强度比给出了较暗日珥的光学厚度τ < 1.0,较亮日珥的光学厚度τ < 2.0。tau_0值允许推断中心线强度的源函数,从而推断具有平均激发温度T_ex = 3750 K的氦3S和3 P能级的相对布居。使用SUMER,我们依次观察到6个光谱窗口,其中包含较高的莱曼线,中性和单电荷原子的“冷”发射线,以及O IV,O V,N V,S V和S VI等离子的“热”发射线。极紫外线显示出显着的最大值,在主要的日珥体,以及“侧位置”的“热”线相对于“冷”线增强。蓝向莱曼系极限(λ <912)的“热”线的线辐射在主日珥体中出现减少。这种吸收在Fe IX/X 171的TRACE图像中也可以看到,它是一个精细的暗结构,只覆盖了主(“冷”)日珥体的一部分。莱曼线显示出随着上能级k = 5到19的增加,线宽和辐射率平滑地减小。当k= 5 ~ 8时,能级粒子数服从玻尔兹曼分布,T_ex >6 *10^4 K; k > 8的能级越高,粒子数越多。莱曼线的较大宽度需要接近“热”EUV线的高非热加宽。相比之下,He II发射与“冷”线更相关。

英文摘要:

We present a comprehensive set of spectral data from two quiescent solar prominences observed in parallel from space and ground: with the VTT, simultaneous two-dimensional imaging of H-beta 4862 and Ca II 8542 yields a constant ratio, indicating small spatial pressure variations over the prominences. With the Gregory, simultaneous spectra of Ca II 8542 and He I 10830 were taken, their widths yielding 8000< T_kin< 9000 K and v_nth<8 km/s. The intensity ratio of the helium triplet components gives an optical thickness of tau < 1.0 for the fainter and tau < 2.0 for the brighter prominence. The tau_0 values allow to deduce the source function for the central line intensities and thus the relative population of the helium 3S and 3P levels with a mean excitation temperature T_ex = 3750 K. With SUMER, we sequentially observed 6 spectral windows containing higher Lyman lines, 'cool' emission lines from neutrals and singly charged atoms, as well as 'hot' emission lines from ions like O IV, O V, N V, S V and S VI. The EUV lines show pronounced maxima in the main prominence body as well as 'side-locations' where the 'hot' lines are enhanced with respect to the 'cool' lines. The line radiance of 'hot' lines blue-wards of the Lyman series limit (lambda<912 A) appear reduced in the main prominence body. This absorption is also visible in TRACE images of Fe IX/X 171 as fine dark structure which covers only parts of the main ('cool') prominence body. The Lyman lines show a smooth decrease of line widths and radiance with increasing upper level k = 5 through 19. For k= 5 through 8 the level population follows a Boltzmann distribution with T_ex >6 *10^4 K; higher levels k > 8 appear more and more overpopulated. The larger widths of the Lyman lines require high non-thermal broadening close to that of 'hot' EUV lines. In contrast, the He II emission is more related to the 'cool' lines.

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