Observations of X-Ray Jets with the Yohkoh Soft X-Ray Telescope

Abstract Time series of Soft X-ray Telescope images have revealed many X-ray jets in the solar corona. The typical size of a jet is 5 × 103–4 × 105 km, the translational velocity is 30–300 km s−1, and the corresponding kinetic energy is estimated to be 1025–1028 erg. Many of the jets are associated with flares in X-ray bright points, emerging flux regions, or active regions. They sometimes occur several times from the same X-ray feature. In some cases, a dark void appears after ejection at the footpoint of the jet. The void seems to be the result of a change in the topology of the X-ray emitting plasma, perhaps due to magnetic reconnection. Some jets show a structure which suggests a helical magnetic field configuration along the jet. One of the jets associated with a flaring bright point was identified as being an Hα surge. In this case, the X-ray bright point is situated just on the Hα bright point at the footpoint of the surge. The top of the surge is not bright in X-rays. We briefly discuss the origin of these newly discovered X-ray jets.