权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Fundamental technical development of the detector system of the solar resonance scattering light by analyzing the ion density and velocity distribution

通过分析离子密度和速度分布进行太阳共振散射光探测器系统的基础技术开发

基本信息

批准号：
07640585
负责人：
IWAGAMI Naomoto
金额：
$ 1.47万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1997
项目状态：
已结题

项目摘要

We studied the possibility to image the oxygen ions which exist in the Earth's magnetotail. As we had had no knowledge of the existence of the oxygen ions in the tail region of the Earth's magnetosphere until several years before, the GEOTAIL spacecraft, which serches for the magnetosphere, identified the oxygen ions with very low temperature and high density. These oxygen ions flow as a beam from the Earth to the tail direction, whose velocity becomes higher as more distant. We will make big progress in studying the dynamics of the magnetosphere, if we can take picutres of the whole magnetosphere by using oxygen ions. The wavelength of the resonant scattering light is subject to the Doppler shifting, as the oxygen ions move relatively to the Sun. The efficiency of the resonant scatter becomes worse when ions are largely Doppler shifted because the width of the resonant scattering lines is several tens of milli-angstrom and the emission line width of the sun light is the same order to … More this. Resonant scatter does not occur essentially to the single emission line as helium, when relative velocity becomes over 50km/sec. Oxygen ions, on the other hand, have three resonant scattering lines which are very close to each other. There are 9 emission lines corresponding to the (singly and doubly ionized) oxygen ion in the solar light, so Oxygen ions can scatter another emission line resonantly when they are subjected to the Doppler shifting by the relative motion. We calculated the geometric factor which show the efficiency of the resonant scatter considering this effect. Also, we simulated the intensity of the scattered light from the tail region of the magnetosphere by the oxygen ions by using the model of the velocity, temperature and density of the oxygen ions from the results of the GEOTAIL spacecraft. Using these values, we concluded that the intensity of the light is 0.1-10 Rayleigh. The result means that we can image the Earth's magnetosphere with the resolution of 1 Re (Earth's radius) by using 25 cm diameter telescope, exposing about 10 minutes. Thus our study show the imaging of the magnetotail is possible in principle. Less

我们研究了对地球磁尾中存在的氧离子进行成像的可能性。由于我们直到几年前才知道地球磁层尾部存在氧离子，所以服务于磁层的GEOTAIL航天器发现了温度很低、密度很高的氧离子。这些氧离子以光束的形式从地球流向尾部，距离越远，尾部的速度就越快。如果我们能用氧离子拍摄整个磁层的照片，我们将在研究磁层动力学方面取得很大进展。当氧离子相对于太阳运动时，共振散射光的波长受到多普勒频移的影响。由于共振散射线的宽度为几十毫角，而太阳光的发射线宽度与…相同，因此当离子发生较大的多普勒频移时，共振散射的效率变差更多的是这个。当相对速度超过50公里/秒时，单发射线基本上不会发生氦的共振散射。另一方面，氧离子有三条相互靠近的共振散射线。太阳光中有9条发射线对应于(单电离和双电离)氧离子，因此当氧离子受到相对运动的多普勒频移时，它们可以共振地散射另一条发射线。考虑到这一影响，我们计算了反映共振散射效率的几何因子。此外，我们还利用GEOTAIL航天器上得到的氧离子速度、温度和密度模型，模拟了氧离子在磁层尾区的散射光强度。使用这些值，我们得出结论，光的强度为0.1-10瑞利。这一结果意味着，我们可以用直径25厘米的望远镜，曝光约10分钟，以1Re(地球半径)的分辨率拍摄地球磁层。因此，我们的研究表明，磁尾成像在原则上是可能的。较少