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

Yohkoh任务于1991年发射，目的是用一套协调的x射线和伽马射线仪器观测太阳耀斑。与之前的太阳活动高峰期飞行的光谱仪相比，Yohkoh上的吹牛晶体光谱仪（BCS）的灵敏度提高了一个数量级，重量和尺寸都更小。该仪器是在英日合作下设计制造的。该仪器的主要科学目标是观测太阳耀斑初始阶段的等离子体运动和燃烧等离子体的瞬态加热和粒子加速。两国的太阳物理学家已经完成了对Yohkoh数据的科学分析。完全蓝移的发射线是在耀斑的初期发现的。这一新发现支持了色球蒸发假说。太阳活动区的硫排放表明活动区存在微耀斑加热的可能性。日冕是非常动态的，由于磁重联，会发生多种活动。

The Yohkoh mission was launched in 1991 for the observation of solar flares with a coordinated set of instruments in X-rays and gamma-rays. The Brag crystal spectrometer(BCS) on Yohkoh has an order of magnitude increased sensitivity with less weight and size, if it is compared to the spectrometers flown in the previous solar activity maximum. The instrument was designed and manufactured under the Anglo-Japanese cooperation. The main scientific goal of this instrument is to observe the plasma motions and the transient heating and particle acceleration of flaring plasma at the initial phases of solar flares. The scientific analyses of the Yohkoh data have been done by solar physicists of the both countries. The completely blueshifted emission line was found in the very beginnings of flares. This new discovery supports the hypothesis of chromospheric evaporation. The sulphur emission from solar active regions suggests a possibility of the microflare heating of active regions. The solar corona is very dynamic and many kinds of activity take place as the result of magnetic reconnection.