Study of solar X-ray albedo by the upper earth atmosphere and fluorescent X-rays using the data obtained by the X-ray astronomy satellite

利用X射线天文卫星获得的数据研究上层地球大气和荧光X射线的太阳X射线反照率

• 批准号: 12640433
• 负责人: ITOH Masayuki
• 金额: $ 0.83万
• 依托单位: Kobe University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12640433/
• 关键词: Solar X-ray; The sun; Albedo; 太陽活動周期; 高層大気; 宇宙塵

We studied the earth albedo of the solar X-ray and its long term variation using die data obtained by the Gas Imaging Spectrometer (GIS) on board the X-ray satellite ASCA The X-ray albedo spectra in the energy range of 0.5-5keV were obtained with the resolution that enables detection of K-lines of several elements for almost the full span of solar activity. The spectra can be described with a model that consists of three elements : (a) 2-temperature thermal emission, (b) modification of the thermal emission through the reflection by the earth atmosphere, and (c) additional emission lines. The component (a) is the averaged emission from the solar coronae. The temperatures of the thermal X-ray emission from the sun stayed almost constant within the statistics of the data, and the values of the two components are 〜300MK and 500-1000MK respectively The intensities of the two components showed variation in accordance with the solar activity cycle, of which amplitude was larger for the higher temperature component. The higher temperature component is probably from the X-ray emission of the solar flares, and the lower temperature component is from the non-flaring coronae. The additional emission lines include K-lines of Mg and Si aside from the K-lines from the atmospheric 0 and Ar. The Mg and Si lines have lower energies and higher intensities than those expected from the main component of the thermal emission from the sun. One of the possible explanations is the ionization non-equilibrium eflect in the solar coronal plasma ASTRO-EII that is to be launched in 2005 is expected to enable same line of research with superior energy resolution.

利用ASCA X射线卫星上的气体成像光谱仪（GIS）获得的数据，研究了太阳X射线在地球上的辐射及其长期变化。获得了能量范围为0.5- 5 keV的X射线辐射谱，其分辨率几乎可以探测到太阳活动的整个时间跨度内几种元素的K线。光谱可以用一个由三个要素组成的模型来描述：（a）2-温度热发射，（B）通过地球大气的反射对热发射进行修改，以及（c）附加发射谱线。分量（a）是来自日冕的平均发射。太阳热X射线辐射的温度在统计范围内基本保持不变，两个分量的值分别为300 ~ 300 MK和500- 1000 MK，两个分量的强度随太阳活动周期而变化，温度较高的分量振幅较大。高温成分可能来自太阳耀斑的X射线辐射，低温成分可能来自非耀斑日冕。除了来自大气0和Ar的K线之外，附加发射线还包括Mg和Si的K线。Mg和Si谱线的能量比太阳热辐射的主要成分预期的能量低，强度高。一种可能的解释是，将于2005年发射的ASTRO-EII太阳日冕等离子体中的电离非平衡效应，预计将能够以上级能量分辨率进行同样的研究。

项目成果

Itoh, M.: "Total Spectrum of the solar X-ray and its long-term variation obtained from earth albedo data of ASCA GIS"The proceedings of the IAU 8-th Asian-Pacific Regional Meeting. Vol.II. 435-436 (2002)

Itoh, M.：“从 ASCA GIS 地球反照率数据获得的太阳 X 射线总光谱及其长期变化”IAU 第 8 届亚太地区会议记录。

Itoh, M. et al.: "Total Spectrum of the solar X-ray and its long-term variation obtained from earth albedo data of ASCA GIS"The Proceedings of the IAU 8th Asian Pacific Regional Meeting. Vol.II. 435-436 (2002)

Itoh, M.等：“从ASCA GIS的地球反照率数据获得的太阳X射线总光谱及其长期变化”IAU第八届亚太地区会议论文集。