论文标题
深色外部差距：温度最低和动态性质的表现
Dark off-limb gap: manifestation of temperature minimum and dynamic nature of the chromosphere
论文作者
论文摘要
我们使用H $β$和CA II8542Å线的高分辨率成像光谱法研究下太阳大气的LIMB发射，并使用彩色成像光谱仪（Chromis）和瑞典1毫秒1-m Solar Telescope上的染色体成像光谱仪（Chromis）获得。 H $β$线翼图像显示了CA II图像中不存在的光球肢和色球圈之间的深度强度差距。我们在一维球面几何形状中计算出LIMB排放的合成光谱，并与观测值吻合。对合成线轮廓的分析表明，由于该层中Balmer线的不透明度和发射率，H $β$线翼图像中的差距映射了光球和色球之间的温度最小区域。然而，与合成轮廓相比，在离外线机翼位置的线芯方面检测到的间隙比合成轮廓更远。我们发现，在模型染色体中需要增加的微扰动性来重现外线机翼中的暗间隙，这表明观察到的H $β$间隙是温度最小值的表现和太阳染色体的动态性质的表现。温度最低会在合成CA II线翼强度中产生少量增强。观察到的未限制线翼线排放量显示出相似的增强，低于温度最低层，附近的光谱肢体边缘附近。
We study off-limb emission of the lower solar atmosphere using high-resolution imaging spectroscopy in the H$β$ and Ca II 8542 Å lines obtained with the CHROMospheric Imaging Spectrometer (CHROMIS) and the CRisp Imaging SpectroPolarimeter (CRISP) on the Swedish 1-m Solar Telescope. The H$β$ line wing images show the dark intensity gap between the photospheric limb and chromosphere which is absent in the Ca II images. We calculate synthetic spectra of the off-limb emissions with the RH code in the one-dimension spherical geometry and find good agreement with the observations. The analysis of synthetic line profiles shows that the gap in the H$β$ line wing images maps the temperature minimum region between the photosphere and chromosphere due to the well known opacity and emissivity gap of Balmer lines in this layer. However, observed gap is detected farther from the line core in the outer line wing positions than in the synthetic profiles. We found that an increased microturbulence in the model chromosphere is needed to reproduce the dark gap in the outer line wing, suggesting that observed H$β$ gap is the manifestation of the temperature minimum and the dynamic nature of the solar chromosphere. The temperature minimum produces a small enhancement in synthetic Ca II line-wing intensities. Observed off-limb Ca II line-wing emissions show similar enhancement below temperature minimum layer near the edge of the photospheric limb.
