PROPERTIES OF THE DIFFUSE NEUTRAL HELIUM IN THE INNER HELIOSPHERE
PROPERTIES OF THE DIFFUSE NEUTRAL HELIUM IN THE INNER HELIOSPHERE
复制标题
日球层内弥散中性氦的性质
DOI：
10.1088/0004-637x/722/2/1411
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
J. Kuhn
中科院分区：
文献类型：
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作者：
E. Moise;J. Raymond;J. Kuhn
哈雷阿卡拉的灵敏 SOLARC 成像分光偏振观测揭示了 He i 1083 nm 线中的漫射日冕表面亮度。一系列观察表明，该信号源自日冕中中性氦原子的“内部来源”。在这里，我们探索了这种冷日冕成分起源于氦离子的可能性，氦离子被近太阳尘埃中和，随后被激发到亚稳态 1s2s3S 状态，然后散射来自太阳盘的光子。这张图片表明，在大约 2-4 R☉ 范围内，日冕尘埃存在缺陷，以解释观测结果的平坦径向亮度分布和较小的速度线宽度。我们发现偏振氦亮度和日冕白光亮度之间存在很强的相关性，这支持了亚稳态氦三重态能级的电子碰撞激发导致我们的偏振信号的论点。
Sensitive SOLARC imaging spectropolarimetric observations from Haleakala reveal a diffuse coronal surface brightness in the He i 1083 nm line. A series of observations suggests that this signal originates from an “inner source” of neutral helium atoms in the solar corona. Here, we explore the possibility that this cold coronal component originates from helium ions that are neutralized by the near-Sun dust and subsequently excited to the metastable 1s2s3S state, which then scatters photons from the solar disk. This picture suggests a deficit of coronal dust inside about 2–4 R☉ in order to account for both the flat radial brightness distribution and the small velocity line width of the observations. We find a strong correlation between the polarized He brightness and coronal white light brightness that supports the argument that electronic collisional excitation of the metastable helium triplet level is responsible for our polarization signal.