Properties of the He I 10830 Å Line in Solar Flares
Properties of the He I 10830 Å Line in Solar Flares
复制标题
太阳耀斑中 He I 10830 Å 谱线的特性
DOI：
--
复制
发表时间：
2008
期刊：
影响因子：
--
通讯作者：
Hui Li
中科院分区：
文献类型：
--
作者：
Q. Du;Hui Li
利用紫金山天文台（PMO）的多通道红外太阳光谱仪（MISS）和太阳与日光层观测站（SOHO）的迈克尔逊多普勒成像仪（MDI）的光谱数据，研究了9次太阳耀斑中He I 10830 A谱线的性质。结果表明，在3 '-8''范围内，当耀斑的GOES X射线等级达到阈值（C4.5）时，He I 10830 A谱线在附近的平静区出现超过连续谱的发射。He I 10830 A谱线发射只在Hα增亮核中被探测到，但与耀斑的大小无关。发现当He I 10830 A谱线在附近连续谱线上表现出过量发射时，Hα和Ca II 8542 A谱线都表现出超过耀斑前强度的增强。He I 10830 A谱线发射偶尔会延伸到黑子本影中，这与以往的研究结果不一致。He I 10830 A谱线的弱分量比主分量更早地从发射转变为吸收。我们的结果有利于光电离重联机制的激发He I 10830 A线。
We study the properties of the He I 10830 A line in nine selected solar flares, using spectral data obtained with the Multi-channel Infrared Solar Spectrograph (MISS) at Purple Mountain Observatory (PMO) and photospheric images from the Michelson Doppler Imager (MDI) onboard the Solar and Heliospheric Observatory (SOHO). Our results indicate that, over an area of 3'– 8', the He I 10830 A line shows emission exceeding the continuum in nearby quiet region when the Geostationary Operations Environmental Satellite (GOES) X-ray class of the flare reaches a threshold value (C4.5). The He I 10830 A line emission is detected only in the kernels of the Hα brightenings, but is not associated with the size of the flare. It is found that, whenever the He I 10830 A line shows excess emission over the nearby continuum both the Hα and the Ca II 8542 A lines display enhanced intensities exceeding their preflare intensities. The He I 10830 A line emission can occasionally extend into the umbra of the involved sunspot, which is inconsistent with previous studies. The weak component of He I 10830 A line changes from emission to absorption earlier than does the main component. Our results favor the photoionization-reconnection mechanism for the excitation of the He I 10830 A line.