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

太阳耀斑是经常发生在太阳黑子附近的瞬时爆炸现象，其温度达到约2000万开氏度。尽管经过多年的研究，高温的原因仍然不清楚。为了了解其中的物理学原理，我们计划在山上建造一个新的日冕仪。Norikura太阳天文台，并获得发生在太阳边缘以外的10^7 K耀斑的白色光图像。1990年，日本研制成功了一颗全自动、口径10厘米的日冕仪，并于1991年8月发射成功。从那时起，我们已经获得了一些耀斑图像上的两个仪器。我们得到了5 × 10^9电子cm ↑ [2]的电子密度<-3>和1 = 1 × 10^8 - 1 × 10^9 cm的几何厚度，其中1 = 10^8 cm的值是一个令人惊讶的和本质上是一个新的结果，因为垂直于视线测量的表观几何尺寸通常是3- 6 × 10^9 cm。这对耀斑理论一定有重要的影响，而我们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，标题中所示的目标正在从新日冕中实现，并且正在与Yohkoh卫星合作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.