Yohkoh results in the context of the high-latitude heliosphere

Designed primarily to study solar activity, Yohkoh includes an X-ray telescope that obtains full-sun coronal images which show a range of features. Coronal X-ray emission-exclusive of flares, is notable for its variability even in the largest structures. A mass ejection event is related to magnetic field reconnection. Such events exhibit both accelerated and decelerated behaviour. Coronal hole temperatures are estimated from the filter ratio method. A plasma component at around 2.10⁶ K is identified. X-ray emission is detected from the South polar coronal hole. A preliminary comparison of Spartan coronagraph images with Yohkoh data suggests that polar plumes or rays are not connected to bright points.