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Detection of 20 million Degree, Superhot Flare Images with a Coronagraph

使用日冕仪检测 2000 万度超热耀斑图像

基本信息

批准号：
63420002
负责人：
HIRAYAMA Tadashi
金额：
$ 16.77万
依托单位：
National Astronomical Observatory
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1991
项目状态：
已结题

项目摘要

The solar flare is transient explosive phenomena often occurring near the sunspots, and it attains to a temperature of some 20 million degree Kelvin. The cause of the high temperature is not known yet in spite of years of research.In order to understand the physics involved we planned to construct a new coronagraph to be built on the Mt. Norikura Solar Observatory and to obtain white light images of the 10^7K flare which occurs beyond the limb of the Sun. Simultaneous observations were anticipated using this coronagraph and a Japanese scientific satellite, Solar-A, dedicated to study flares with X-ray imaing device.A fully automated, 10cm aperture coronagraph was completed in 1990 and begun routine operation since Nov. 1990, and the satellite was successfully launched in Aug. 1991. Since then we have acquired a few flare images on both instruments. And we obtained the electron density of 5x10^9 electrons cm^<-3> and the geometrical thickness l=1x10^8-1x10^9cm, of which a value of l=10^8cm is a surprise and an essentially new result because the apparent geometrical size measured perpendicularly to the line of sight is usually 3-6x10^9cm. This must have important bearing upon flare theory, and we have just begun to investigate the problem. Polarimetric observation will also be conducted soon for determination of prominence magnetic fields.In summary, we can conclude that the aim shown in the title is being achieved from the new coronagraph and further research is being continued with the collaboration of the Yohkoh satellite.

太阳耀斑是一种经常发生在太阳黑子附近的瞬时爆炸现象，它的温度可达2000万开尔文左右。尽管进行了多年的研究，但高温的原因尚不清楚。为了了解其中的物理原因，我们计划在这座山上建造一台新的日冕仪。Norikura太阳天文台，并获得发生在太阳边缘之外的10.7K耀斑的白光图像。预计将使用该日冕仪和专门用于研究耀斑的日本科学卫星Solar-A进行同步观测。一台全自动、口径10厘米的日冕仪于1990年完成，自1990年11月开始常规运行，卫星于1991年8月成功发射。从那时起，我们在两台仪器上都获得了一些耀斑图像。得到了5×10~(-9)电子的电子密度cm~(-3)和几何厚度L=1x10~(^8)~1x10~(^9)cm，其中L=10~(^8)cm是一个令人惊讶的新结果，因为垂直于视线测量的视几何尺寸通常为3~6x10~(^9)cm。这肯定对耀斑理论有重要影响，我们才刚刚开始研究这个问题。此外，天文台亦会在短期内进行偏振观测，以测定日冕磁场。总括而言，我们可以得出结论，新的日冕仪已达到标题所示的目标，并与Yohkoh卫星合作，继续进行进一步的研究。