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arXiv 1302.6936astro-ph.SR
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光球层和低色球层中波的能量:IV。Ca II H谱的反演结果

The energy of waves in the photosphere and lower chromosphere: IV. Inversion results of Ca II H spectra

C. Beck, R. Rezaei, K. G. Puschmann

摘要:

大多数静态的一维大气模型在安静的太阳预测上升的气体温度在色球层,但数值模拟只产生增加的亮度温度。我们调查太阳色球层的热结构,来自LTE反演的Ca II H光谱在QS和活动区。我们调查的温度分层之间的差异,在QS的磁场和无场区域,QS和AR之间。我们测定了单个钙亮粒(BG)的能量含量。光球层温度波动的均方根值小于100 K,色球层温度波动的均方根值为200-300 K。QS的平均温度分层没有表现出明显的色球温度上升,相反的AR的情况。我们发现一个能量含量约为7* 10 E18 J的BG,重复约160秒的节奏。BG的前体具有约200公里的垂直范围和约1微米的水平范围。与合成NLTE配置文件的比较证实,在QS的太阳色球振荡之间的大气中的辐射平衡和一个温和的色球温度上升。在大约600 km高度的光球磁场浓度附近,二维x-z温度图显示出几乎水平的冠状结构,其范围为几个Mm。QS区域和AR之间的巨大差异,以及AR和非LTE参考光谱的更好匹配表明,磁加热过程比通常假设的更重要。由LTE反演得到的QS中的温度波动平均不足以维持稳定的色球温度上升。空间和垂直分辨的温度结构的信息,使人们能够详细调查的拓扑结构和演变的热结构在太阳低层大气。

英文摘要:

Most static 1D atmosphere models in the quiet Sun predict a rise of the gas temperature at chromospheric layers, but numerical simulations only yield an increase in the brightness temperature. We investigate the thermal structure in the solar chromosphere as derived from an LTE inversion of Ca II H spectra in QS and active regions. We investigate the temperature stratifications on differences between magnetic and field-free regions in the QS, and between QS and ARs. We determine the energy content of individual calcium bright grains (BGs). The rms temperature fluctuations are below 100 K in the photosphere and 200-300 K in the chromosphere. The average temperature stratification in the QS does not exhibit a clear chromospheric temperature rise, opposite to the AR case. We find an energy content of about 7*10E18 J for BGs that repeat with a cadence of about 160 secs. The precursors of BGs have a vertical extent of about 200 km and a horizontal extent of about 1 Mm. The comparison of observed with synthetic NLTE profiles confirms that the solar chromosphere in the QS oscillates between an atmosphere in radiative equilibrium and one with a moderate chromospheric temperature rise. Two-dimensional x-z temperature maps exhibit nearly horizontal canopy-like structures with a few Mm extent around photospheric magnetic field concentrations at a height of about 600 km. The large difference between QS regions and ARs, and the better match of AR and non-LTE reference spectra suggest that magnetic heating processes are more important than commonly assumed. The temperature fluctuations in QS derived by the LTE inversion do not suffice on average to maintain a stationary chromospheric temperature rise. The spatially and vertically resolved information on the temperature structure allows one to investigate in detail the topology and evolution of the thermal structure in the lower solar atmosphere.

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