UK-Japan Cooperative Study of Solar Flares with the SOLAR-A Spacecraft

SOLAR-A （Yohkoh）任务于1991年8月30日成功发射。探测器上的科学仪器状况良好，正在传回太阳x射线和伽马射线波长的新数据。由英国和日本合作开发和制造的布拉格晶体光谱仪揭示了日冕和耀斑诊断的新方面。在亚C级活动中发生了类似耀斑的色球蒸发，这可能是了解日冕加热机制的关键。首次以改进的光谱分辨率拍摄了小M级耀斑中的类氢铁光谱。软x射线发射线的全蓝移光谱清楚地表明太阳耀斑中色球蒸发的证据。日冕中的元素丰度有时与光球中的元素丰度不同，并随太阳耀斑的发展而变化。连接在一起的工作站中的数据分析软件为鹿儿岛航天中心和美国宇航局深空网络站的下行数据提供了有效的分析系统。

The SOLAR-A (Yohkoh) mission was successfully launched on August 30, 1991.The onboard scientific instruments have been in good condition and returning new data of the sun in X-ray and gamma-ray wavelengths. Bragg crystal spectrometer, developed and manufactured under the UK-Japan collaboration, revealed new aspects of coronal and flare diagnostics. A flare-like chromospheric evaporation takes place in an sub C class activity, which may have a key to understand the heating mechanism of solar corona. Hydrogen like iron spectra in small M class flares were taken for the first time with an improved spectral resolution. Totally blueshifted spectra of soft X-ray emission lines clearly indicate the evidence of chromospheric evaporation in solar flares. Element abundances in the corona are sometimes different from those in the photosphere and change according to the development of solar flares. Data analysis softwares in the workstations linked together, provide an efficient analysis system of data downlinked both at Kagoshima "Space Center and at Deep Space Network Stations, NASA.