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Time series of SXT (Soft X-ray Telescope) images have revealed many jet-like features in the solar corona. Typical size of the “jet” is 5 × 103 – 4 × 105 km, the typical projected velocity is 30 – 300 km/s, and the kinetic energy estimated to be 1025 – 1028 erg. Many of the jets are associated with flare-like bright points or sub-flares. Three typical examples are discussed, including an X-ray jet identified with an Hα surge. It is suggested that magnetic reconnection is one of the possible mechanisms to produce these X-ray jets.

Fe XVII soft X-ray spectral emission lines are examined using data from the Flat Crystal Spectrometer (FCS) on the Solar Maximum Mission satellite. Results are compared with theoretical calculations and with other recent observational results. Disparate Ðndings from di †erent studies on the inferred opacity of the bright resonance line at 15.01 and on its center-to-limb behavior are reviewed. Present limi-A tations on the use of resonance scattering to infer coronal plasma densities and absolute elemental abundances are discussed. An analysis is made of the temperature-insensitive ratio of the 15.01 line of A Fe XVII to the optically thin 16.78 line. This analysis shows that approximately half of the photons A expected in the 15.01 line are missing from the bright emission cores of quiescent active regions on the A solar disk ; the missing fraction increases at most by 50% near the solar limb. If the missing Ñux has been resonantly scattered out of the line of sight, then the equivalent optical depth at line center of the 15.01 line is on the disk, based on a simple escape probability treatment for a slab geometry. A q 0 D 2 This suggests that the e †ects of resonance scattering for other FCS lines, with the possible exception of the O VIII doublet at 18.97should be negligible for quiescent active region conditions. This is consis-A , tent with the lack of systematic center-to-limb dependence found previously for FCS lines other than Fe XVII at 15.01Y ohkoh Soft X-ray Telescope measurements of the expected lines of sight for active A . regions as a function of location on the solar disk, and resonance scattering results from other soft X-ray active region data sets all support a trend of increased opacity at the limb compared to disk center.