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

太阳耀斑是一种短暂的爆炸现象，经常发生在太阳黑子附近，它的温度达到大约2000万开尔文。尽管经过多年的研究，造成高温的原因仍不清楚。为了了解所涉及的物理问题，我们计划在Norikura山太阳天文台建造一个新的日冕仪，并获得10^7K耀斑的白光图像，它发生在太阳的边缘之外。同时观测预计使用日冕仪和日本科学卫星，太阳- a，致力于研究耀斑的x射线成像设备。一个完全自动化的10厘米孔径日冕仪于1990年完成，并于1990年11月开始常规操作，卫星于1991年8月成功发射。从那以后，我们在两台仪器上获得了一些耀斑图像。我们得到了5 × 10^9个电子的电子密度cm^<-3>，几何厚度l=1 × 10^8-1 × 10^9cm，其中l=10^8cm是一个令人惊讶的新结果，因为垂直于视线测量的表观几何尺寸通常为3-6 × 10^9cm。这一定对耀斑理论有重要的影响，而我们才刚刚开始研究这个问题。不久还将进行偏振观测，以确定日珥磁场。总之，我们可以得出结论，新的日冕仪正在实现标题中所示的目标，并在Yohkoh卫星的合作下继续进行进一步的研究。

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.